1
|
Shayeganfar F, Shahsavari R. Deep Learning Method to Accelerate Discovery of Hybrid Polymer-Graphene Composites. Sci Rep 2021; 11:15111. [PMID: 34301976 PMCID: PMC8302643 DOI: 10.1038/s41598-021-94085-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 07/05/2021] [Indexed: 11/17/2022] Open
Abstract
Interfacial encoded properties of polymer adlayers adsorbed on the graphene (GE) and silicon dioxide (SiO2) have been constituted a scaffold for the creation of new materials. The holistic understanding of nanoscale intermolecular interaction of 1D/2D polymer assemblies on substrate is the key to bottom-up design of molecular devices. We develop an integrated multidisciplinary approach based on electronic structure computation [density functional theory (DFT)] and big data mining [machine learning (ML)] in parallel with neural network (NN) and statistical analysis (SA) to design hybrid polymers from assembly on substrate. Here we demonstrate that interfacial pressure and structural deformation of polymer network adsorbed on GE and SiO2 offer unique directions for the fabrication of 1D/2D polymers using only a small number of simple molecular building blocks. Our findings serve as the platform for designing a wide range of typical inorganic heterostructures, involving noncovalent intermolecular interaction observed in many nanoscale electronic devices.
Collapse
Affiliation(s)
- Farzaneh Shayeganfar
- Department of Civil and Environmental Engineering, Rice University, Houston, TX, 77005, USA. .,Department of Physics and Energy Engineering, Amirkabir University of Technology, 15916-3967, Tehran, Iran.
| | | |
Collapse
|
2
|
Fallas PZ, Kimzey JQ, Hundi P, Islam MT, Noveron JC, Alvarez PJJ, Shahsavari R. Combinatorial Analysis of Sparse Experiments on Photocatalytic Performance of Cement Composites: A Route toward Optimizing Multifunctional Materials for Water Purification. Langmuir 2021; 37:5699-5706. [PMID: 33900778 DOI: 10.1021/acs.langmuir.1c00654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Blending TiO2 and cement to create photocatalytic composites holds promise for low-cost, durable water treatment. However, the efficiency of such composites hinges on cross-effects of several parameters such as cement composition, type of photocatalyst, and microstructure, which are poorly understood and require extensive combinatorial tests to discern. Here, we report a new combinatorial data science approach to understand the influence of various photocatalytic cement composites based on limited datasets. Using P25 nanoparticles and submicron-sized anatase as representative TiO2 photocatalysts and methyl orange and 1,4-dioxane as target organic pollutants, we demonstrate that the cement composition is a more influential factor on photocatalytic activity than the cement microstructure and TiO2 type and particle size. Among the various cement constituents, belite and ferrite had strong inverse correlation with photocatalytic activity, while natural rutile had a positive correlation, which suggests optimization opportunities by manipulating the cement composition. These results were discerned by screening 7806 combinatorial functions that capture cross-effects of multiple compositional phases and obtaining correlation scores. We also report •OH radical generation, cement aging effects, TiO2 leaching, and strategies to regenerate photocatalytic surfaces for reuse. This work provides several nonintuitive correlations and insights on the effect of cement composition and structure on performance, thus advancing our knowledge on development of scalable photocatalytic materials for drinking water treatment in rural and resource-limited areas.
Collapse
Affiliation(s)
- Pamela Zuniga Fallas
- NSF ERC for Nanotechnology Enabled Water Treatment (NEWT), Rice University, Houston, Texas 77005, United States
- Dept. of Civil and Environmental Engineering, Rice University, Houston, Texas 77005, United States
| | - Jaime Quesada Kimzey
- Escuela de Química, Instituto Tecnológico de Costa Rica, Cartago 159-7050, Costa Rica
| | - Prabhas Hundi
- Dept. of Civil and Environmental Engineering, Rice University, Houston, Texas 77005, United States
| | - Md Tariqul Islam
- NSF ERC for Nanotechnology Enabled Water Treatment (NEWT), Rice University, Houston, Texas 77005, United States
- Dept. of Chemistry, University of Texas, El Paso, El Paso, Texas 79968, United States
| | - Juan C Noveron
- NSF ERC for Nanotechnology Enabled Water Treatment (NEWT), Rice University, Houston, Texas 77005, United States
- Dept. of Chemistry, University of Texas, El Paso, El Paso, Texas 79968, United States
| | - Pedro J J Alvarez
- NSF ERC for Nanotechnology Enabled Water Treatment (NEWT), Rice University, Houston, Texas 77005, United States
- Dept. of Civil and Environmental Engineering, Rice University, Houston, Texas 77005, United States
| | - Rouzbeh Shahsavari
- C-Crete Technologies, 13000 Murphy Rd, Ste 102, Stafford, Texas 7477, United States
| |
Collapse
|
3
|
Hosseini E, Zakertabrizi M, Habibnejad Korayem A, Carbone P, Esfandiar A, Shahsavari R. Mechanical hydrolysis imparts self-destruction of water molecules under steric confinement. Phys Chem Chem Phys 2021; 23:5999-6008. [PMID: 33666607 DOI: 10.1039/d0cp06186g] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Decoding behavioral aspects associated with the water molecules in confined spaces such as an interlayer space of two-dimensional nanosheets is key for the fundamental understanding of water-matter interactions and identifying unexpected phenomena of water molecules in chemistry and physics. Although numerous studies have been conducted on the behavior of water molecules in confined spaces, their reach stops at the properties of the planar ice-like formation, where van der Waals interactions are the predominant interactions and many questions on the confined space such as the possibility of electron exchange and excitation state remain unsettled. We used density functional theory and reactive molecular dynamics to reveal orbital overlap and induction bonding between water molecules and graphene sheets under much less pressure than graphene fractures. Our study demonstrates high amounts of charge being transferred between water and the graphene sheets, as the interlayer space becomes smaller. As a result, the inner face of the graphene nanosheets is functionalized with hydroxyl and epoxy functional groups while released hydrogen in the form of protons either stays still or traverses a short distance inside the confined space via the Grotthuss mechanism. We found signatures of a new hydrolysis mechanism in the water molecules, i.e. mechanical hydrolysis, presumably responsible for relieving water from extremely confined conditions. This phenomenon where water reacts under extreme confinement by disintegration rather than forming ice-like structures is observed for the first time, illustrating the prospect of treating ultrafine porous nanostructures as a driver for water splitting and material functionalization, potentially impacting the modern design of nanofilters, nanochannels, nano-capacitators, sensors, and so on.
Collapse
Affiliation(s)
- Ehsan Hosseini
- Nanomaterials Research Centre, School of Civil Engineering, Iran University of Science and Technology, Tehran, Iran.
| | - Mohammad Zakertabrizi
- Nanomaterials Research Centre, School of Civil Engineering, Iran University of Science and Technology, Tehran, Iran.
| | - Asghar Habibnejad Korayem
- Nanomaterials Research Centre, School of Civil Engineering, Iran University of Science and Technology, Tehran, Iran. and Department of Civil Engineering, Monash University, Clayton, Victoria, Australia
| | - Paola Carbone
- School of Chemical Engineering and Analytical Science, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Ali Esfandiar
- Department of Physics, Sharif University of Technology, Tehran 11155-9161, Iran.
| | - Rouzbeh Shahsavari
- Department of Civil and Environmental Engineering, Rice University, Houston, Texas 77005, USA.
| |
Collapse
|
4
|
Abstract
In this work, an approach to upcycling plastic waste (PW) products is presented. The method relies on flash Joule heating (FJH) to convert PW into flash graphene (FG). In addition to FG, the process results in the formation of carbon oligomers, hydrogen, and light hydrocarbons. In order to make high-quality graphene, a sequential alternating current (AC) and direct current (DC) flash is used. The FJH process requires no catalyst and works for PW mixtures, which makes the process suitable for handling landfill PW. The energy required to convert PW to FG is ∼23 kJ/g or ∼$125 in electricity per ton of PW, potentially making this process economically attractive for scale-up. The FG was characterized by Raman spectroscopy and had an I2D/IG peak ratio up to 6 with a low-intensity D band. Moreover, transmission electron microscopy and X-ray diffraction analysis show that the FG is turbostratic with an interlayer spacing of 3.45 Å. The large interlayer spacing will facilitate its dispersion in liquids and composites. Analysis of FG dispersions in 1% Pluronic aqueous solution shows that concentrations up to 1.2 mg/mL can be achieved. The carbon oligomers that distilled from the process were characterized by Fourier transform infrared spectroscopy and have chemical structures similar to the starting PW. Initial analysis of gas-phase products shows the formation of considerable amounts of hydrogen along with other light hydrocarbons. As graphene is naturally occurring and shows a low toxicity profile, this could be an environmentally beneficial method to upcycle PW.
Collapse
Affiliation(s)
- Wala A Algozeeb
- Department of Chemistry, Rice University, 6100 Main Street, Houston, Texas 77005, United States
| | - Paul E Savas
- Department of Chemistry, Rice University, 6100 Main Street, Houston, Texas 77005, United States
| | - Duy Xuan Luong
- Department of Chemistry, Rice University, 6100 Main Street, Houston, Texas 77005, United States
| | - Weiyin Chen
- Department of Chemistry, Rice University, 6100 Main Street, Houston, Texas 77005, United States
| | - Carter Kittrell
- Department of Chemistry, Rice University, 6100 Main Street, Houston, Texas 77005, United States
| | - Mahesh Bhat
- C-Crete Technologies, Stafford, Texas 77477, United States
| | | | - James M Tour
- Department of Chemistry, Rice University, 6100 Main Street, Houston, Texas 77005, United States
- Department of Materials Science and NanoEngineering, Rice University, 6100 Main Street, Houston, Texas 77005, United States
- Smalley-Curl Institute, NanoCarbon Center and Welch Institute for Advanced Materials, Rice University, 6100 Main Street, Houston, Texas 77005, United States
| |
Collapse
|
5
|
Hosseini E, Zakertabrizi M, Habibnejad Korayem A, Zaker Z, Shahsavari R. Orbital Overlapping through Induction Bonding Overcomes the Intrinsic Delamination of 3D-Printed Cementitious Binders. ACS Nano 2020; 14:9466-9477. [PMID: 32491835 DOI: 10.1021/acsnano.0c02038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
3D printing of cementitious materials holds a great promise for construction due to its rapid, consistent, modular, and geometry-controlled ability. However, its major drawback is low cohesion in the interlayer region. Herein, we report a combined experimental and computational approach to understand and control fabrication of 3D-printed cementitious materials with significantly enhanced interlayer strength using multimaterial 3D printing, in which the composition, function, and structure of the materials are programmed. Our results show that the intrinsic low interlayer cohesion is caused by excess moisture and time lag that block the majority of valuable interactions in the interlayer zone between the adjacent cement matrices. As a remedy, a thin epoxy layer is introduced as an intermediator between the adjacent extruded layers, both to improve the interlayer cohesion and to extend the possible time delay between printed adjacent layers. Our ab initio calculations demonstrate that an orbital overlap between the calcium ions, as the main electrophilic part of the cement structure, and the hydroxyl groups, as the nucleophilic part of the epoxy, create strong interfacial absorption sites. These electronic absorptions lead to several iono-covalent bonds between the cement matrix and epoxy, leading to significant improvements in tensile, shear, and compressive strengths as well as ductility of the 3D-printed composites. This is verified by our experimental data, which showed an average of 84% improvement in interlayer bonding. The upward augmentation of interlayer bonding helps 3D printing cementitious material to overcome their intrinsic limitation of weak interlayer cohesion, thereby mitigating/eliminating the key bottleneck of additive manufacturing in constructing materials.
Collapse
Affiliation(s)
- Ehsan Hosseini
- Nanomaterials Research Centre, School of Civil Engineering, Iran University of Science and Technology, Tehran 1684613114, Iran
| | - Mohammad Zakertabrizi
- Nanomaterials Research Centre, School of Civil Engineering, Iran University of Science and Technology, Tehran 1684613114, Iran
| | - Asghar Habibnejad Korayem
- Nanomaterials Research Centre, School of Civil Engineering, Iran University of Science and Technology, Tehran 1684613114, Iran
- Department of Civil Engineering, Monash University, Melbourne, VIC 3800, Australia
| | - Zafar Zaker
- Nanomaterials Research Centre, School of Civil Engineering, Iran University of Science and Technology, Tehran 1684613114, Iran
| | - Rouzbeh Shahsavari
- Department of Civil and Environmental Engineering, Rice University, Houston, Texas 77005, United States
- C-Crete Technologies LLC, Stafford, Texas 77477, United States
| |
Collapse
|
6
|
Faghihnasiri M, Beheshtian J, Shayeganfar F, Shahsavari R. Phase transition and mechanical properties of cesium bismuth silver halide double perovskites (Cs 2AgBiX 6, X = Cl, Br, I): a DFT approach. Phys Chem Chem Phys 2020; 22:5959-5968. [PMID: 32123885 DOI: 10.1039/c9cp05342e] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Double perovskite-based silver and bismuth Cs2AgBiX6 (X = Cl, Br, I) have shown a bright future for the development of low-risk photovoltaic devices due to their high stability and non-toxicity of their elements, unlike Pb-based perovskites. Despite the great focus on the optoelectronic properties of Cs2AgBiX6 double perovskites, there are limited studies on the behavior of their structural properties. Herein, we carefully examined the cubic structure of Cs2AgBiX6 double perovskites, identifying a pseudo-cubic (ps-cubic) phase, which is similar to the initial cubic phase. The observed pseudo-cubic phase is more consistent with previous experimental results demonstrating higher elastic properties, which are useful for designing optoelectronic devices.
Collapse
Affiliation(s)
- Mahdi Faghihnasiri
- Computational Materials Science Laboratory, Nano Research and Training Center, NRTC, Iran
| | | | | | | |
Collapse
|
7
|
Amiri M, Beheshtian J, Shayeganfar F, Faghihnasiri M, Shahsavari R, Ramazani A. Electro-Optical Properties of Monolayer and Bilayer Pentagonal BN: First Principles Study. Nanomaterials (Basel) 2020; 10:nano10030440. [PMID: 32121427 PMCID: PMC7153586 DOI: 10.3390/nano10030440] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 02/25/2020] [Accepted: 02/25/2020] [Indexed: 01/29/2023]
Abstract
Two-dimensional hexagonal boron nitride (hBN) is an insulator with polar covalent B-N bonds. Monolayer and bilayer pentagonal BN emerge as an optoelectronic material, which can be used in photo-based devices such as photodetectors and photocatalysis. Herein, we implement spin polarized electron density calculations to extract electronic/optical properties of mono- and bilayer pentagonal BN structures, labeled as B2N4, B3N3, and B4N2. Unlike the insulating hBN, the pentagonal BN exhibits metallic or semiconducting behavior, depending on the detailed pentagonal structures. The origin of the metallicity is attributed to the delocalized boron (B) 2p electrons, which has been verified by electron localized function and electronic band structure as well as density of states. Interestingly, all 3D networks of different bilayer pentagonal BN are dynamically stable unlike 2D structures, whose monolayer B4N2 is unstable. These 3D materials retain their metallic and semiconductor nature. Our findings of the optical properties indicate that pentagonal BN has a visible absorption peak that is suitable for photovoltaic application. Metallic behavior of pentagonal BN has a particular potential for thin-film based devices and nanomaterial engineering.
Collapse
Affiliation(s)
- Mehran Amiri
- Department of Chemistry, Faculty of Science, Shahid Rajaee Teacher Training University, 16788-15811 Tehran, Iran; (M.A.); (M.F.)
| | - Javad Beheshtian
- Department of Chemistry, Faculty of Science, Shahid Rajaee Teacher Training University, 16788-15811 Tehran, Iran; (M.A.); (M.F.)
- Correspondence: (J.B.); (F.S.)
| | - Farzaneh Shayeganfar
- Department of Physics and Energy Engineering, Amirkabir University of Technology, 15916-39675 Tehran, Iran
- Department of Civil and Environmental Engineering, Rice University, Houston, TX 77005, USA;
- Correspondence: (J.B.); (F.S.)
| | - Mahdi Faghihnasiri
- Department of Chemistry, Faculty of Science, Shahid Rajaee Teacher Training University, 16788-15811 Tehran, Iran; (M.A.); (M.F.)
| | - Rouzbeh Shahsavari
- Department of Civil and Environmental Engineering, Rice University, Houston, TX 77005, USA;
| | - Ali Ramazani
- Department of Mechanical Engineering, MIT, Cambridge, MA 02139, USA;
| |
Collapse
|
8
|
Hundi P, Shahsavari R. Deep Learning to Speed up the Development of Structure-Property Relations For Hexagonal Boron Nitride and Graphene. Small 2019; 15:e1900656. [PMID: 30968576 DOI: 10.1002/smll.201900656] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Revised: 03/13/2019] [Indexed: 06/09/2023]
Abstract
Structure-property maps play a key role in accelerated materials discovery. The current norm for developing these maps includes computationally expensive physics-based simulations. Here, the capabilities of deep learning agents are explored such as convolutional neural networks (CNNs) and multilayer perceptrons (MLPs) to predict structure-property relations and reduce dependence on simulations. This study contains simulated hexagonal boron nitride (h-BN) microstructures damaged by various levels of radiation and temperature, with the objective to predict their residual strengths from the final atomic positions. By developing low dimensional physical descriptors to statistically describe the defects, these results show that purpose-specific microstructure representation can help in achieving a good prediction accuracy at low computational cost. Furthermore, the adaptability of the trained deep learning agents is explored to predict structure-property maps of other 2D materials using transfer learning. It is shown that in order to achieve good predictions accuracy (≈95% R2 ), an agent that is training for the first time ("learning from scratch") requires 23-45% of simulated data, whereas an agent adapting to a different material ("transfer learning") requires only about 10% or less. This suggests that transfer learning is a potential game changer in material discovery and characterization approaches.
Collapse
Affiliation(s)
- Prabhas Hundi
- Department of Civil and Environmental Engineering, Rice University, Houston, TX, 77005, USA
| | - Rouzbeh Shahsavari
- Department of Civil and Environmental Engineering, Rice University, Houston, TX, 77005, USA
- C-Crete Technologies LLC, Stafford, TX, 77477, USA
| |
Collapse
|
9
|
Hosseini E, Zakertabrizi M, Habibnejad Korayem A, Shahsavari R. Tunable, Multifunctional Ceramic Composites via Intercalation of Fused Graphene Boron Nitride Nanosheets. ACS Appl Mater Interfaces 2019; 11:8635-8644. [PMID: 30719919 DOI: 10.1021/acsami.8b19409] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Ternary two-dimensional (2D) materials such as fused graphene-boron nitride (GBN) nanosheets exhibit attractive physical and tunable properties far beyond their parent structures. Although these features impart several multifunctional properties in various matrices, a fundamental understanding on the nature of the interfacial interactions of these ternary 2D materials with host matrices and the role of their individual components has been elusive. Herein, we focus on intercalated GBN/ceramic composites as a model system and perform a series of density functional theory calculations to fill this knowledge gap. Propelled by more polarity and negative Gibbs free energy, our results demonstrate that GBN is more water-soluble than graphene and hexagonal boron nitride (h-BN), making it a preferred choice for slurry preparation and resultant intercalations. Further, a chief attribute of the intercalated GBN/ceramic is the formation of covalent C-O and B-O bonds between the two structures, changing the hybridization of GBN from sp2 to sp3. This change, combined with the electron release in the vicinity of the interfacial regions, leads to several nonintuitive mechanical and electrical alterations of the composite such as exhibiting higher young's modulus, strength, and ductility as well as sharp decline in the band gap. As a limiting case, though both tobermorite ceramic and h-BN are wide band gap materials, their intercalated composite becomes a p-type semiconductor, contrary to intuition. These multifunctional features, along with our fundamental electronic descriptions of the origin of property change, provide key guidelines for synthesizing next generation of multifunctional bilayer ceramics with remarkable properties on demand.
Collapse
Affiliation(s)
- Ehsan Hosseini
- School of Civil Engineering , Iran University of Science and Technology , Tehran , Iran
| | - Mohammad Zakertabrizi
- School of Civil Engineering , Iran University of Science and Technology , Tehran , Iran
| | - Asghar Habibnejad Korayem
- School of Civil Engineering , Iran University of Science and Technology , Tehran , Iran
- Department of Civil Engineering , Monash University Melbourne , Clayton , Victoria 3800 , Australia
| | - Rouzbeh Shahsavari
- Department of Civil and Environmental Engineering , Rice University , Houston , Texas 77005 , United States
- C-Crete Technologies LLC , Stafford , Texas 77477 , United States
| |
Collapse
|
10
|
Shayeganfar F, Beheshtian J, Shahsavari R. Boron nitride nanochannels encapsulating a water/heavy water layer for energy applications. RSC Adv 2019; 9:5901-5907. [PMID: 35517256 PMCID: PMC9060902 DOI: 10.1039/c8ra09925a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 02/06/2019] [Indexed: 11/21/2022] Open
Abstract
Water interaction and transport through nanochannels of two-dimensional (2D) nanomaterials hold great promises in several applications including separation, energy harvesting and drug delivery. However, the fundamental underpinning of the electronic phenomena at the interface of such systems is poorly understood. Inspired by recent experiments, herein, we focus on water/heavy water in boron nitride (BN) nanochannels – as a model system – and report a series of ab initio based density functional theory (DFT) calculations on correlating the stability of adsorption and interfacial properties, decoding various synergies in the complex interfacial interactions of water encapsulated in BN nanocapillaries. We provide a comparison of phonon vibrational modes of water and heavy water (D2O) captured in bilayer BN (BLBN) to compare their mobility and group speed as a key factor for separation mechanisms. This finding, combined with the fundamental insights into the nature of the interfacial properties, provides key hypotheses for the design of nanochannels. Single layer water (SLW) on BN layer and encapsulated between bilayer BN (BLBN) as nanochannel.![]()
Collapse
Affiliation(s)
- Farzaneh Shayeganfar
- Department of Civil and Environmental Engineering
- Rice University
- Houston
- USA
- Department of Energy Engineering and Physics
| | - Javad Beheshtian
- Department of Chemistry
- Shahid Rajaee Teacher Training University
- Iran
| | - Rouzbeh Shahsavari
- Department of Civil and Environmental Engineering
- Rice University
- Houston
- USA
- Department of Material Science and NanoEngineering
| |
Collapse
|
11
|
Han X, Wang T, Owuor PS, Hwang SH, Wang C, Sha J, Shen L, Yoon J, Wang W, Salvatierra RV, Ajayan PM, Shahsavari R, Lou J, Zhao Y, Tour JM. Ultra-Stiff Graphene Foams as Three-Dimensional Conductive Fillers for Epoxy Resin. ACS Nano 2018; 12:11219-11228. [PMID: 30408411 DOI: 10.1021/acsnano.8b05822] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Conductive epoxy composites are of great interest due to their applications in electronics. They are usually made by mixing powdered conductive fillers with epoxy. However, the conductivity of the composite is limited by the low filler content because increasing filler content causes processing difficulties and reduces the mechanical properties of the epoxy host. We describe here the use of ultra-stiff graphene foams (uGFs) as three-dimensional (3D) continuous conductive fillers for epoxy resins. The powder metallurgy method was used to produce the dense uGFs monoliths that resulted in a very high filler content of 32 wt % in the uGF-epoxy composite, while the density of epoxy was only increased by 0.09 g/cm3. The composite had an electrical conductivity of 41.0 ± 6.3 S/cm, which is among the highest of all of the polymer-based composites with non-conductive polymer matrices and comparable with the conductive polymer matrices reported to date. The compressive modulus of the composite showed a remarkable improvement of >1700% compared to pure epoxy. We have demonstrated that the 3D uGF filler substantially improves the conductivity and reinforces the polymer matrix with a high filler content while retaining a density similar to that of the epoxy alone.
Collapse
Affiliation(s)
- Xiao Han
- School of Materials Science and Engineering , Beihang University , Beijing 100191 , China
| | | | | | | | - Chao Wang
- Center for Composite Materials and Structures , Harbin Institute of Technology , Harbin 150080 , China
| | - Junwei Sha
- School of Materials Science and Engineering, Tianjin Key Laboratory of Composite and Functional Materials , Tianjin University , Tianjin 300350 , China
| | | | | | | | | | | | | | | | - Yan Zhao
- School of Materials Science and Engineering , Beihang University , Beijing 100191 , China
| | | |
Collapse
|
12
|
Shahsavari R, Hwang SH. Size- and Shape-Controlled Synthesis of Calcium Silicate Particles Enables Self-Assembly and Enhanced Mechanical and Durability Properties. Langmuir 2018; 34:12154-12166. [PMID: 30252480 DOI: 10.1021/acs.langmuir.8b00917] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Calcium silicate (CS)-based materials are ubiquitous in diverse industries ranging from cementitious materials to bone tissue engineering and drug delivery. As a symbolic example, concrete is the most widely used synthetic material on the planet. This large consumption entails significant negative environmental footprint, which calls for innovative strategies to develop greener concrete with improved properties (to do more with less). Herein, we focus on the physicochemical properties of novel spherical calcium silicate particles with an extremely narrow size distribution and report their promising potential as fundamental building blocks. We demonstrate a scalable size- and shape-controlled synthesis protocol to yield highly spherical CS submicron particles, leading to favorable aggregation mechanisms and thus self-assembly of the bulk ensemble. This optimized kinetics-controlled synthesis is governed by suitable stoichiometric ratio of calcium over silicon, type and concentration of the surfactant, and molar ratio of the alkaline solution. Our extensive nano/micro/macro-characterization results show that the bulk ensemble exhibits many superior properties, such as improved strength, toughness, ductility, and durability, paving the path for bottom-up science-based engineering of concrete.
Collapse
Affiliation(s)
- Rouzbeh Shahsavari
- C-Crete Technologies LLC , 13000 Murphy Road, Suite 102 , Houston , Texas 77477 , United States
| | | |
Collapse
|
13
|
Abstract
Water confined to nanopores such as carbon nanotubes (CNTs) exhibits different states, enabling the study of solidlike water nanotubes (WNTs) and the potential application of their properties due to confined effects. Herein, we report the interfacial interaction and particular stabilized boundaries of confined WNTs within CNTs and boron nitride nanotubes (BNNTs) using first-principles calculations. We demonstrate that the intermolecular potential of nanotube walls exerts diameter-dependent additive or subtractive van der Waals (vdW) pressure on the WNTs, altering the phase boundaries. Our results reveal that the most stable WNT@CNT is associated with a CNT diameter of 10.5 Å. By correlating the stability of WNTs with interfacial properties such as the vdW pressure and vibrational phonon modes of confined WNTs, we decode and compare various synergies in water interaction and stabilized states within the CNTs and BNNTs, including interfacial properties of WNT@BNNTs that are more significant than those of WNT@CNTs. Our results suggest that the transition of a water tube to an ice tube is strongly dependent on the diameter of the confining CNT or BNNT, providing new insights on leveraging the interfacial interaction mechanism of confined WNTs and their potential application for fabricating nanochannels and nanocapacitors.
Collapse
Affiliation(s)
- Farzaneh Shayeganfar
- Department of Civil and Environmental Engineering , Rice University , Houston , Texas 77005 , United States
- Department of Energy Engineering and Physics , Amirkabir University , 14588 Tehran , Iran
| | - Javad Beheshtian
- Department of Chemistry , Shahid Rajaee Teacher Training University , 16875-163 Tehran , Iran
| | - Rouzbeh Shahsavari
- Department of Civil and Environmental Engineering , Rice University , Houston , Texas 77005 , United States
| |
Collapse
|
14
|
Abstract
By performing an extensive 150+ first-principles calculations, this work demonstrates how the exotic properties of emerging 2D hBN nanosheets (e.g., ultrahigh surface area, high mechanical and thermal tolerance) can be coupled strategically (via exfoliation and geometrical compatibility) with the lamellar nanostructure of calcium-silicate crystals to introduce "reinforcement" at the basal plane of materials, i.e., the smallest possible scale. Probing mechanical properties show significant enhancement in strength, toughest, stiffness and strain, providing key guidelines to intercalate a suite of emerging 2D materials in ceramics for the bottom-up design and fabrication of ultrahigh performance and multifunctional ceramic composites.
Collapse
Affiliation(s)
- Rouzbeh Shahsavari
- Department of Civil and Environmental Engineering, Department of Material Science and NanoEngineering, and Smalley Institute for Nanoscale Science and Technology Rice University , Houston, Texas 77005, United States
| |
Collapse
|
15
|
Hwang SH, Shahsavari R. Intrinsic Size Effect in Scaffolded Porous Calcium Silicate Particles and Mechanical Behavior of Their Self-Assembled Ensembles. ACS Appl Mater Interfaces 2018; 10:890-899. [PMID: 29241004 DOI: 10.1021/acsami.7b15803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Scaffolded porous submicron particles with well-defined diameter, shape, and pore size have profound impacts on drug delivery, bone-tissue replacement, catalysis, sensors, photonic crystals, and self-healing materials. However, understanding the interplay between pore size, particle size, and mechanical properties of such ultrafine particles, especially at the level of individual particles and their ensemble states, is a challenge. Herein, we focus on porous calcium-silicate submicron particles with various diameters-as a model system-and perform extensive 900+ nanoindentations to completely map out their mechanical properties at three distinct structural forms from individual submicron particles to self-assembled ensembles to pressure-induced assembled arrays. Our results demonstrate a notable "intrinsic size effect" for individual porous submicron particles around ∼200-500 nm, induced by the ratio of particle characteristic diameter to pore characteristic size distribution. Increasing this ratio results in a brittle-to-ductile transition where the toughness of the submicron particles increases by 120%. This size effect becomes negligible as the porous particles form superstructures. Nevertheless, the self-assembled arrays collectively exhibit increasing elastic modulus as a function of applied forces, while pressure-induced compacted arrays exhibit no size effect. This study will impact tuning properties of individual scaffolded porous particles and can have implications on self-assembled superstructures exploiting porosity and particle size to impart new functionalities.
Collapse
Affiliation(s)
- Sung Hoon Hwang
- Department of Material Science and Nano Engineering, Rice University , Houston, Texas 77005, United States
| | - Rouzbeh Shahsavari
- Department of Material Science and Nano Engineering, Rice University , Houston, Texas 77005, United States
- Department of Civil and Environmental Engineering, Rice University , Houston, Texas 77005, United States
- The Smalley-Curl Institute, Rice University, Rice University , Houston, Texas 77005, United States
- C-Crete Technologies LLC , 13000 Murphy Rd, Ste 102, Stafford, Texas 77477, United States
| |
Collapse
|
16
|
Abstract
Hybrid 3D nanoarchitectures by covalent connection of 1D and 2D nanomaterials are currently in high demands to overcome the intrinsic anisotropy of the parent materials. This letter reports the junction configuration-mediated thermal transport properties of Pillared Graphene (PGN) using reverse nonequilibrium molecular dynamics simulations. The asymmetric junctions can offer ∼20% improved in-plane thermal transport in PGN, unlike the intuition that their wrinkled graphene sheets cause phonon scattering. This asymmetric trait, which entails lower phonon scattering provides a new degree of freedom to boost thermal properties of PGN and potentially other hybrid nanostructures.
Collapse
Affiliation(s)
- Navid Sakhavand
- Department of Civil and Environmental Engineering, ‡Department of Material Science and NanoEngineering, and §Smalley Institute for Nanoscale Science and Technology, Rice University , Houston, Texas 77005, United States
| | - Rouzbeh Shahsavari
- Department of Civil and Environmental Engineering, ‡Department of Material Science and NanoEngineering, and §Smalley Institute for Nanoscale Science and Technology, Rice University , Houston, Texas 77005, United States
| |
Collapse
|
17
|
Hwang SH, Miller JB, Shahsavari R. Biomimetic, Strong, Tough, and Self-Healing Composites Using Universal Sealant-Loaded, Porous Building Blocks. ACS Appl Mater Interfaces 2017; 9:37055-37063. [PMID: 28991434 DOI: 10.1021/acsami.7b12532] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Many natural materials, such as nacre and dentin, exhibit multifunctional mechanical properties via structural interplay between compliant and stiff constituents arranged in a particular architecture. Herein, we present, for the first time, the bottom-up synthesis and design of strong, tough, and self-healing composite using simple but universal spherical building blocks. Our composite system is composed of calcium silicate porous nanoparticles with unprecedented monodispersity over particle size, particle shape, and pore size, which facilitate effective loading and unloading with organic sealants, resulting in 258% and 307% increases in the indentation hardness and elastic modulus of the compacted composite. Furthermore, heating the damaged composite triggers the controlled release of the nanoconfined sealant into the surrounding area, enabling moderate recovery in strength and toughness. This work paves the path towards fabricating a novel class of biomimetic composites using low-cost spherical building blocks, potentially impacting bone-tissue engineering, insulation, refractory and constructions materials, and ceramic matrix composites.
Collapse
|
18
|
Biernacki JJ, Bullard JW, Sant G, Banthia N, Brown K, Glasser FP, Jones S, Ley T, Livingston R, Nicoleau L, Olek J, Sanchez F, Shahsavari R, Stutzman PE, Sobolev K, Prater T. Cements in the 21 st Century: Challenges, Perspectives, and Opportunities. J Am Ceram Soc 2017; 100:2746-2773. [PMID: 28966345 PMCID: PMC5615410 DOI: 10.1111/jace.14948] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
In a book published in 1906, Richard Meade outlined the history of portland cement up to that point1. Since then there has been great progress in portland cement-based construction materials technologies brought about by advances in the materials science of composites and the development of chemical additives (admixtures) for applications. The resulting functionalities, together with its economy and the sheer abundance of its raw materials, have elevated ordinary portland cement (OPC) concrete to the status of most used synthetic material on Earth. While the 20th century was characterized by the emergence of computer technology, computational science and engineering, and instrumental analysis, the fundamental composition of portland cement has remained surprisingly constant. And, although our understanding of ordinary portland cement (OPC) chemistry has grown tremendously, the intermediate steps in hydration and the nature of calcium silicate hydrate (C-S-H), the major product of OPC hydration, remain clouded in uncertainty. Nonetheless, the century also witnessed great advances in the materials technology of cement despite the uncertain understanding of its most fundamental components. Unfortunately, OPC also has a tremendous consumption-based environmental impact, and concrete made from OPC has a poor strength-to-weight ratio. If these challenges are not addressed, the dominance of OPC could wane over the next 100 years. With this in mind, this paper envisions what the 21st century holds in store for OPC in terms of the driving forces that will shape our continued use of this material. Will a new material replace OPC, and concrete as we know it today, as the preeminent infrastructure construction material?
Collapse
Affiliation(s)
| | - Jeffrey W Bullard
- National Institute of Standards and Technology (NIST), Gaithersburg, MD
| | | | | | | | | | - Scott Jones
- National Institute of Standards and Technology (NIST), Gaithersburg, MD
| | - Tyler Ley
- Oklahoma State University, Stillwater, OK
| | | | - Luc Nicoleau
- BASF Construction Materials and Systems, Trostberg, Germany
| | - Jan Olek
- Purdue University, West La Fayette, IN
| | | | | | - Paul E Stutzman
- National Institute of Standards and Technology (NIST), Gaithersburg, MD
| | | | | |
Collapse
|
19
|
Shayeganfar F, Beheshtiyan J, Neek-Amal M, Shahsavari R. Electro- and opto-mutable properties of MgO nanoclusters adsorbed on mono- and double-layer graphene. Nanoscale 2017; 9:4205-4218. [PMID: 28290570 DOI: 10.1039/c6nr08586e] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Inspired by recent experiments, the trapping of molecules in 2D materials has gained increasing attention due to the unique ability of the molecules to modulate the electronic and optical properties of 2D materials, which calls for fundamental understanding and predictive design strategies. Herein, we focus on mono- and double-layer graphene encapsulating various MgO clusters and explore their diverse electronic and optical properties using a number of high-level first-principles calculations. By correlating the stability of adsorption, geometry, charge transfer, band structures, optical absorption spectrum, and the van der Waals pressure, our results decode various synergies in electro- and opto-mutable properties of MgO/graphene systems. We found that 2D-MgO flakes on graphene layers exhibit surface polarization effects - in contrast to their isolated neutral flakes - and show a significant charge transfer from graphene to n-doped flakes, breaking the symmetry of graphene layers. We obtained a van der Waals pressure of ∼0.7 (0.9) GPa on bilayer graphene encapsulating MgO nanoclusters, which matches extremely well with experiment. While there is one quantum emission in the visible light region for a single MgO flake, a wide range of visible light is accessible for MgO on mono- and double-layer graphene. Overall, these findings provide new physical insights and design strategies to modulate 2D materials with several applications in optoelectronics while significantly broadening the spectrum of strategies for fabricating new hybrid 2D heterostructures by encapsulating external molecules.
Collapse
Affiliation(s)
- Farzaneh Shayeganfar
- Department of Civil and Environmental Engineering, Rice University, Houston, TX 77005, USA. and Institute for Advanced Technologies, Shahid Rajaee Teacher Training University, 16875-163, Lavizan, Tehran, Iran
| | - Javad Beheshtiyan
- Institute for Advanced Technologies, Shahid Rajaee Teacher Training University, 16875-163, Lavizan, Tehran, Iran and Department of Physics, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerpen, Belgium
| | - Mehdi Neek-Amal
- Institute for Advanced Technologies, Shahid Rajaee Teacher Training University, 16875-163, Lavizan, Tehran, Iran and Department of Physics, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerpen, Belgium
| | - Rouzbeh Shahsavari
- Department of Civil and Environmental Engineering, Rice University, Houston, TX 77005, USA. and Department of Material Science and NanoEngineering, Rice University, Houston, TX 77005, USA and Smalley Institute for Nanoscale Science and Technology, Rice University, Houston, TX 77005, USA
| |
Collapse
|
20
|
Zhang N, Carrez P, Shahsavari R. Screw-Dislocation-Induced Strengthening-Toughening Mechanisms in Complex Layered Materials: The Case Study of Tobermorite. ACS Appl Mater Interfaces 2017; 9:1496-1506. [PMID: 28009497 DOI: 10.1021/acsami.6b13107] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Nanoscale defects such as dislocations have a profound impact on the physics of crystalline materials. Understanding and characterizing the motion of screw dislocation and its corresponding effects on the mechanical properties of complex low-symmetry materials has long been a challenge. Herein, we focus on triclinic tobermorite, as a model system and a crystalline analogue of layered hydrated cement, and report for the first time how the motion of screw dislocation can influence the strengthening-toughening relationship, imparting brittle-to-ductile transitions. By applying shear loading in tobermorite systems with single and dipole screw dislocations, we observe dislocation jogs around the dislocation core, which increases the yield shear stress and the work-of-fracture when the dislocation lines are along the [100] and [010] directions. Our results demonstrate that the dislocation core acts as a bottleneck for the initial straight gliding to induce intralaminar gliding, which consequently leads to a significant improvement in the mechanical properties. Together, the fundamental knowledge gained in this work on the role of the motion of the dislocation core on the mechanical properties provides an improved understanding of deformation mechanisms in cementitious materials and other complex layered systems, providing new hypotheses and design guidelines for the development of strong, ductile, and tough materials.
Collapse
Affiliation(s)
| | - Philippe Carrez
- Unité Matériaux et Transformations, CNRS UMR8207, Bât. C6, Université de Lille 1 , Villeneuve d'Ascq 59655, France
| | | |
Collapse
|
21
|
Tao L, Theruvakkattil Sreenivasan S, Shahsavari R. Interlaced, Nanostructured Interface with Graphene Buffer Layer Reduces Thermal Boundary Resistance in Nano/Microelectronic Systems. ACS Appl Mater Interfaces 2017; 9:989-998. [PMID: 28073276 DOI: 10.1021/acsami.6b09482] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Improving heat transfer in hybrid nano/microelectronic systems is a challenge, mainly due to the high thermal boundary resistance (TBR) across the interface. Herein, we focus on gallium nitride (GaN)/diamond interface-as a model system with various high power, high temperature, and optoelectronic applications-and perform extensive reverse nonequilibrium molecular dynamics simulations, decoding the interplay between the pillar length, size, shape, hierarchy, density, arrangement, system size, and the interfacial heat transfer mechanisms to substantially reduce TBR in GaN-on-diamond devices. We found that changing the conventional planar interface to nanoengineered, interlaced architecture with optimal geometry results in >80% reduction in TBR. Moreover, introduction of conformal graphene buffer layer further reduces the TBR by ∼33%. Our findings demonstrate that the enhanced generation of intermediate frequency phonons activates the dominant group velocities, resulting in reduced TBR. This work has important implications on experimental studies, opening up a new space for engineering hybrid nano/microelectronics.
Collapse
Affiliation(s)
- Lei Tao
- Department of Civil and Environmental Engineering, Rice University , Houston, Texas 77005, United States
| | | | - Rouzbeh Shahsavari
- Smalley Institute for Nanoscale Science and Technology, Rice University , Houston, Texas 77005, United States
| |
Collapse
|
22
|
Abstract
Hydrogen storage capacities have been studied on newly designed three-dimensional pillared boron nitride (PBN) and pillared graphene boron nitride (PGBN). We propose these novel materials based on the covalent connection of BNNTs and graphene sheets, which enhance the surface and free volume for storage within the nanomaterial and increase the gravimetric and volumetric hydrogen uptake capacities. Density functional theory and molecular dynamics simulations show that these lithium- and oxygen-doped pillared structures have improved gravimetric and volumetric hydrogen capacities at room temperature, with values on the order of 9.1-11.6 wt % and 40-60 g/L. Our findings demonstrate that the gravimetric uptake of oxygen- and lithium-doped PBN and PGBN has significantly enhanced the hydrogen sorption and desorption. Calculations for O-doped PGBN yield gravimetric hydrogen uptake capacities greater than 11.6 wt % at room temperature. This increased value is attributed to the pillared morphology, which improves the mechanical properties and increases porosity, as well as the high binding energy between oxygen and GBN. Our results suggest that hybrid carbon/BNNT nanostructures are an excellent candidate for hydrogen storage, owing to the combination of the electron mobility of graphene and the polarized nature of BN at heterojunctions, which enhances the uptake capacity, providing ample opportunities to further tune this hybrid material for efficient hydrogen storage.
Collapse
Affiliation(s)
- Farzaneh Shayeganfar
- Institute for Advanced Technologies, Shahid Rajaee Teacher Training University , 16875-163 Lavizan, Tehran, Iran
| | | |
Collapse
|
23
|
Kim ND, Metzger A, Hejazi V, Li Y, Kovalchuk A, Lee SK, Ye R, Mann JA, Kittrell C, Shahsavari R, Tour JM. Microwave Heating of Functionalized Graphene Nanoribbons in Thermoset Polymers for Wellbore Reinforcement. ACS Appl Mater Interfaces 2016; 8:12985-12991. [PMID: 27140722 DOI: 10.1021/acsami.6b01756] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Here, we introduce a systematic strategy to prepare composite materials for wellbore reinforcement using graphene nanoribbons (GNRs) in a thermoset polymer irradiated by microwaves. We show that microwave absorption by GNRs functionalized with poly(propylene oxide) (PPO-GNRs) cured the composite by reaching 200 °C under 30 W of microwave power. Nanoscale PPO-GNRs diffuse deep inside porous sandstone and dramatically enhance the mechanics of the entire structure via effective reinforcement. The bulk and the local mechanical properties measured by compression and nanoindentation mechanical tests, respectively, reveal that microwave heating of PPO-GNRs and direct polymeric curing are major reasons for this significant reinforcement effect.
Collapse
Affiliation(s)
- Nam Dong Kim
- Department of Chemistry, ‡Department of Civil and Environmental Engineering, §The NanoCarbon Center, and ∥Department of Material Science and NanoEngineering, Rice University , 6100 Main Street, Houston, Texas 77005, United States
| | - Andrew Metzger
- Department of Chemistry, ‡Department of Civil and Environmental Engineering, §The NanoCarbon Center, and ∥Department of Material Science and NanoEngineering, Rice University , 6100 Main Street, Houston, Texas 77005, United States
| | - Vahid Hejazi
- Department of Chemistry, ‡Department of Civil and Environmental Engineering, §The NanoCarbon Center, and ∥Department of Material Science and NanoEngineering, Rice University , 6100 Main Street, Houston, Texas 77005, United States
| | - Yilun Li
- Department of Chemistry, ‡Department of Civil and Environmental Engineering, §The NanoCarbon Center, and ∥Department of Material Science and NanoEngineering, Rice University , 6100 Main Street, Houston, Texas 77005, United States
| | - Anton Kovalchuk
- Department of Chemistry, ‡Department of Civil and Environmental Engineering, §The NanoCarbon Center, and ∥Department of Material Science and NanoEngineering, Rice University , 6100 Main Street, Houston, Texas 77005, United States
| | - Seoung-Ki Lee
- Department of Chemistry, ‡Department of Civil and Environmental Engineering, §The NanoCarbon Center, and ∥Department of Material Science and NanoEngineering, Rice University , 6100 Main Street, Houston, Texas 77005, United States
| | - Ruquan Ye
- Department of Chemistry, ‡Department of Civil and Environmental Engineering, §The NanoCarbon Center, and ∥Department of Material Science and NanoEngineering, Rice University , 6100 Main Street, Houston, Texas 77005, United States
| | - Jason A Mann
- Department of Chemistry, ‡Department of Civil and Environmental Engineering, §The NanoCarbon Center, and ∥Department of Material Science and NanoEngineering, Rice University , 6100 Main Street, Houston, Texas 77005, United States
| | - Carter Kittrell
- Department of Chemistry, ‡Department of Civil and Environmental Engineering, §The NanoCarbon Center, and ∥Department of Material Science and NanoEngineering, Rice University , 6100 Main Street, Houston, Texas 77005, United States
| | - Rouzbeh Shahsavari
- Department of Chemistry, ‡Department of Civil and Environmental Engineering, §The NanoCarbon Center, and ∥Department of Material Science and NanoEngineering, Rice University , 6100 Main Street, Houston, Texas 77005, United States
| | - James M Tour
- Department of Chemistry, ‡Department of Civil and Environmental Engineering, §The NanoCarbon Center, and ∥Department of Material Science and NanoEngineering, Rice University , 6100 Main Street, Houston, Texas 77005, United States
| |
Collapse
|
24
|
Abstract
Although boron nitride nanotubes (BNNT) and hexagonal-BN (hBN) are superb one-dimensional (1D) and 2D thermal conductors respectively, bringing this quality into 3D remains elusive. Here, we focus on pillared boron nitride (PBN) as a class of 3D BN allotropes and demonstrate how the junctions, pillar length and pillar distance control phonon scattering in PBN and impart tailorable thermal conductivity in 3D. Using reverse nonequilibrium molecular dynamics simulations, our results indicate that although a clear phonon scattering at the junctions accounts for the lower thermal conductivity of PBN compared to its parent BNNT and hBN allotropes, it acts as an effective design tool and provides 3D thermo-mutable features that are absent in the parent structures. Propelled by the junction spacing, while one geometrical parameter, e.g., pillar length, controls the thermal transport along the out-of-plane direction of PBN, the other parameter, e.g., pillar distance, dictates the gross cross-sectional area, which is key for design of 3D thermal management systems. Furthermore, the junctions have a more pronounced effect in creating a Kapitza effect in the out-of-plane direction, due to the change in dimensionality of the phonon transport. This work is the first report on thermo-mutable properties of hybrid BN allotropes and can potentially impact thermal management of other hybrid 3D BN architectures.
Collapse
Affiliation(s)
- Navid Sakhavand
- Department of Civil and Environmental Engineering, Rice University , Houston, Texas 77005, United States
| | - Rouzbeh Shahsavari
- Department of Civil and Environmental Engineering, Rice University , Houston, Texas 77005, United States
- Department of Material Science and NanoEngineering, Rice University , Houston, Texas 77005, United States
- Smalley Institute for Nanoscale Science and Technology, Rice University , Houston, Texas 77005, United States
| |
Collapse
|
25
|
Sakhavand N, Shahsavari R. Universal composition–structure–property maps for natural and biomimetic platelet–matrix composites and stacked heterostructures. Nat Commun 2015; 6:6523. [DOI: 10.1038/ncomms7523] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2014] [Accepted: 02/03/2015] [Indexed: 11/09/2022] Open
|
26
|
Jalilvand S, Shahsavari R. Molecular mechanistic origin of nanoscale contact, friction, and scratch in complex particulate systems. ACS Appl Mater Interfaces 2015; 7:3362-3372. [PMID: 25552227 DOI: 10.1021/am506411h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Nanoscale contact mechanisms, such as friction, scratch, and wear, have a profound impact on physics of technologically important particulate systems. Determining the key underlying interparticle interactions that govern the properties of the particulate systems has been long an engineering challenge. Here, we focus on particulate calcium-silicate-hydrate (C-S-H) as a model system and use atomistic simulations to decode the interplay between crystallographic directions, structural defects, and atomic species on normal and frictional forces. By exhibiting high material inhomogeneity and low structural symmetry, C-S-H provides an excellent system to explore various contact-induced nanoscale deformation mechanisms in complex particulate systems. Our findings provide a deep fundamental understanding of the role of inherent material features, such as van der Waals versus Coulombic interactions and the role of atomic species, in controlling the nanoscale normal contact, friction, and scratch mechanisms, thereby providing de novo insight and strategies for intelligent modulation of the physics of the particulate systems. This work is the first report on atomic-scale investigation of the contact-induced nanoscale mechanisms in structurally complex C-S-H materials and can potentially open new opportunities for knowledge-based engineering of several other particulate systems such as ceramics, sands, and powders and self-assembly of colloidal systems in general.
Collapse
Affiliation(s)
- Soroosh Jalilvand
- Department of Civil and Environmental Engineering, ‡Department of Material Science and NanoEngineering, and §Smalley Institute for Nanoscale Science and Technology, Rice University , Houston, Texas 77005, United States
| | | |
Collapse
|
27
|
Shahsavari R, Chen L. Screw dislocations in complex, low symmetry oxides: core structures, energetics, and impact on crystal growth. ACS Appl Mater Interfaces 2015; 7:2223-2234. [PMID: 25565446 DOI: 10.1021/am5091808] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Determining the atomic structure and the influence of defects on properties of low symmetry oxides have long been an engineering pursuit. Here, we focus on five thermodynamically reversible monoclinic and orthorhombic polymorphs of dicalcium silicates (Ca2SiO3)-a key cement constituent-as a model system and use atomistic simulations to unravel the interplay between the screw dislocation core energies, nonplanar core structures, and Peierls stresses along different crystallographic planes. Among different polymorphs, we found that the α polymorphs (α-C2S) has the largest Peierls stress, corresponding to the most brittle polymorph, which make it attractive for grinding processes. Interestingly, our analyses indicate that this polymorphs has the lowest dislocation core energy, making it ideal for reactivity and crystal growth. Generally, we identified the following order in terms of grinding efficiency based on screw dislocation analysis, α-C2S > αH-C2S > αL-C2S > β-C2S > γ-C2S, and the following order in term of reactivity, α -C2S > αL-C2S > γ-C2S > αH-C2S > β-C2S. This information, combined with other deformation-based mechanisms, such as twinning and edge dislocation, can provide crucial insights and guiding hypotheses for experimentalists to tune the cement grinding mechanisms and reactivity processes for an overall optimum solution with regard to both energy consumption and performance. Our findings significantly broaden the spectrum of strategies for leveraging both crystallographic directions and crystal symmetry to concurrently modulate mechanics and crystal growth processes within an identical chemical composition.
Collapse
Affiliation(s)
- Rouzbeh Shahsavari
- Department of Civil and Environmental Engineering, ‡Department of Material Science and NanoEngineering, §Smalley Institute for Nanoscale Science and Technology, Rice University , Houston, Texas 77005, United States
| | | |
Collapse
|
28
|
Sakhavand N, Shahsavari R. Synergistic Behavior of Tubes, Junctions, and Sheets Imparts Mechano-Mutable Functionality in 3D Porous Boron Nitride Nanostructures. J Phys Chem C Nanomater Interfaces 2014; 118:22730-22738. [PMID: 25289114 PMCID: PMC4183370 DOI: 10.1021/jp5044706] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 07/14/2014] [Indexed: 06/03/2023]
Abstract
One-dimensional (1D) boron nitride nanotube (BNNT) and 2D hexagonal BN (h-BN) are attractive for demonstrating fundamental physics and promising applications in nano-/microscale devices. However, there is a high anisotropy associated with these BN allotropes as their excellent properties are either along the tube axis or in-plane directions, posing an obstacle in their widespread use in technological and industrial applications. Herein, we report a series of 3D BN prototypes, namely, pillared boron nitride (PBN), by fusing single-wall BNNT and monolayer h-BN aimed at filling this gap. We use density functional theory and molecular dynamics simulations to probe the diverse mechano-mutable properties of PBN prototypes. Our results demonstrate that the synergistic effect of the tubes, junctions, and sheets imparts cooperative deformation mechanisms, which overcome the intrinsic limitations of the PBN constituents and provide a number of superior characteristics including 3D balance of strength and toughness, emergence of negative Poisson's ratio, and elimination of strain softening along the armchair orientation. These features, combined with the ultrahigh surface area and lightweight structure, render PBN as a 3D multifunctional template for applications in graphene-based nanoelectronics, optoelectronics, gas storage, and functional composites with fascinating in-plane and out-of-plane tailorable properties.
Collapse
Affiliation(s)
- Navid Sakhavand
- Department of Civil
and Environmental Engineering, Department of Material Science and
NanoEngineering, and Smalley Institute for Nanoscale Science and Technology, Rice University, Houston, Texas 77005, United States
| | - Rouzbeh Shahsavari
- Department of Civil
and Environmental Engineering, Department of Material Science and
NanoEngineering, and Smalley Institute for Nanoscale Science and Technology, Rice University, Houston, Texas 77005, United States
| |
Collapse
|
29
|
Sakhavand N, Muthuramalingam P, Shahsavari R. Toughness governs the rupture of the interfacial H-bond assemblies at a critical length scale in hybrid materials. Langmuir 2013; 29:8154-8163. [PMID: 23713817 DOI: 10.1021/la4014015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The geometry and material property mismatch across the interface of hybrid materials with dissimilar building blocks make it extremely difficult to fully understand the lateral chemical bonding processes and design nanocomposites with optimal performance. Here, we report a combined first-principles study, molecular dynamics modeling, and theoretical derivations to unravel the detailed mechanisms of H-bonding, deformation, load transfer, and failure at the interface of polyvinyl alcohol (PVA) and silicates, as an example of hybrid materials with geometry and property mismatch across the interface. We identify contributing H-bonds that are key to adhesion and demonstrate a specific periodic pattern of interfacial H-bond network dictated by the interface mismatch and intramolecular H-bonding. We find that the maximum toughness, incorporating both intra- and interlayer strain energy contributions, govern the existence of optimum overlap length and thus the rupture of interfacial (interlayer) H-bond assemblies in natural and synthetic hybrid materials. This universally valid result is in contrast to the previous reports that correlate shear strength with rupture of H-bonds assemblies at a finite overlap length. Overall, this work establishes a unified understanding to explain the interplay between geometric constraints, interfacial H-bonding, materials characteristics, and optimal mechanical properties in hybrid organic-inorganic materials.
Collapse
Affiliation(s)
- Navid Sakhavand
- Department of Civil and Environmental Engineering, Rice University, Houston, Texas 77005, USA
| | | | | |
Collapse
|
30
|
Abstract
The use of empirical force fields is now a standard approach in predicting the properties of hydrated oxides which are omnipresent in both natural and engineering applications. Transferability of force fields to analogous hydrated oxides without rigorous investigations may result in misleading property predictions. Herein, we focus on two common empirical force fields, the simple point charge ClayFF potential and the core-shell potential to study tobermorite minerals, the most prominent family of Calcium-Silicate-Hydrates that are complex hydrated oxides. We benchmark the predictive capabilities of these force fields against first principles results. While the structural information seem to be in close agreement with DFT results, we find that for higher order properties such as elastic constants, the core-shell potential quantitatively improves upon the simple point charge model, and shows a larger degree of transferability to complex materials. In return, to remedy the deficiencies of the simple point charge potential for hydrated calcio-silicates, we suggest using both structural data and elasticity data for potential calibration, a new force field potential, CSH-FF. This re-parameterized version of ClayFF is then applied to simulating an atomistic model of cement (Pellenq et al., PNAS, 2009). We demonstrate that this force field improves the predictive capabilities of ClayFF, being considerably less computational intensive than the core-shell model.
Collapse
Affiliation(s)
- Rouzbeh Shahsavari
- Department of Civil and Environmental Engineering, MIT, 77 Massachusetts Av., Cambridge, 02139 MA, USA
| | | | | |
Collapse
|
31
|
Shahsavari R, Ehsani-Zonouz A, Houshmand M, Salehnia A, Ahangari G, Firoozrai M. Plasma glucose lowering effect of the wild Satureja khuzestanica Jamzad essential oil in diabetic rats: role of decreased gluconeogenesis. Pak J Biol Sci 2009; 12:140-5. [PMID: 19579934 DOI: 10.3923/pjbs.2009.140.145] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
This study was to evaluate the effect of the wild SKEO on activities and genes expression of hepatic Glycogen Phosphorylase (GP) and phosphoenolpyruvate carboxykinase (PEPCK) in normal and diabetic rats. The wild SKEO was orally administered at different doses (50 and 100 mg/kg/day) to normal as well as diabetic rats for 21 days. The levels of mRNA were determined using the quantitative real-time RT-PCR technique. The plasma glucose concentrations of diabetic rats receiving SKEO (100 mg kg(-1)) compared with diabetic control were significantly decreased. Hepatic GP activity and its mRNA levels of diabetic rats treated with SKEO moderately increased. The activity of hepatic PEPCK and its mRNA levels were significantly decreased in normal rats treated with SKEO (100 mg kg(-1)). The enhancement of PEPCK activity and its mRNA levels of diabetic treated rats with SEKO (100 mg kg(-1)) was significantly decreased compared with diabetic control. In conclusion, an excessive inhibition of PEPCK in liver of diabetic rats treated with the wild SKEO may contribute to the plasma glucose lowering action of SKEO that seems to be in relation with antioxidant properties of SKEO.
Collapse
Affiliation(s)
- R Shahsavari
- Department of Biochemistry, School of Medicine, Iran University of Medical Sciences, Hemmat Highway, Tehran, Iran
| | | | | | | | | | | |
Collapse
|