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Sigalas NI, van Kraaij SAT, Venetsanos F, Anogiannakis SD, Theodorou DN, Lyulin AV. Measuring Oxygen Solubility in Amorphous and Semicrystalline Polyolefins Using Test Particle Insertion: A Comparative Study of Polyethylene and Isotactic Polypropylene. J Phys Chem B 2024; 128:9284-9296. [PMID: 39290092 PMCID: PMC11440608 DOI: 10.1021/acs.jpcb.4c05106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/19/2024]
Abstract
The test particle insertion method is used to study the solubility of oxygen in two commonly used polymers: polyethylene (PE) and isotactic polypropylene (iPP). Amorphous samples for both polymers were prepared by means of Monte Carlo and molecular dynamics simulations, and the oxygen solubility was measured across different temperatures. The solubility-temperature dependence for iPP proved to be nonmonotonic due to the interplay between binding and reorganizational enthalpy, while for PE, it appeared to be monotonic based on the available data in the studied temperature range. A broad comparison to experiments and simulations is included. Further oxygen insertions were also performed in semicrystalline PE and iPP samples at ambient temperature, and the obtained values were compared to a linear relationship which correlates the solubility in the purely amorphous phase with the solubility in the crystalline phase. The solubility of PE closely follows the linear relationship, while iPP exhibits some divergence. All the semicrystalline samples were previously annealed at elevated temperatures for long periods (a few μs), and a strong effect of annealing was observed on the structure and the solubility of iPP. A well-developed iPP lamellar structure emerged at longer annealing times, while PE develops that structure already in the early crystallization stages. The solubility of semicrystalline iPP samples with lamellar morphology exhibited better agreement with extrapolated solubility values of the amorphous state─the extrapolation was made using a linear relationship connecting solubility in the purely amorphous phase and solubility in mixed phases (amorphous and crystalline). Results on the correlation of the solubility with the local structural ordering are also present.
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Affiliation(s)
- Nikolaos I Sigalas
- Soft Matter and Biological Physics Group, Department of Applied Physics, Technische Universiteit Eindhoven, 5600 MB Eindhoven, The Netherlands
- DPI, P.O. Box 902, 5600 AX Eindhoven, The Netherlands
| | - Stan A T van Kraaij
- Soft Matter and Biological Physics Group, Department of Applied Physics, Technische Universiteit Eindhoven, 5600 MB Eindhoven, The Netherlands
| | - Fotis Venetsanos
- Computational Materials Science and Engineering Group, School of Chemical Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece
| | - Stefanos D Anogiannakis
- Computational Materials Science and Engineering Group, School of Chemical Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece
- DPI, P.O. Box 902, 5600 AX Eindhoven, The Netherlands
| | - Doros N Theodorou
- Computational Materials Science and Engineering Group, School of Chemical Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece
- DPI, P.O. Box 902, 5600 AX Eindhoven, The Netherlands
| | - Alexey V Lyulin
- Soft Matter and Biological Physics Group, Department of Applied Physics, Technische Universiteit Eindhoven, 5600 MB Eindhoven, The Netherlands
- Center for Computational Energy Research (CCER), P.O. Box 513, 5600 MB Eindhoven, The Netherlands
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Warkotsch D, Christiansen H, Zierenberg J, Janke W. Pulling on grafted flexible polymers can cause twisted bundles. SOFT MATTER 2024; 20:4916-4927. [PMID: 38868862 DOI: 10.1039/d4sm00093e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2024]
Abstract
Bundles of semiflexible polymers can twist at low temperatures to balance energy gain from attraction and energy cost from bending. This raises the question whether twisting can be also observed for bundles of rather flexible grafted polymers stretched out by pulling force. Here, we address this question using Monte Carlo computer simulations of small bundles. Our data show that for weak forces F < Fl, intertwined globular conformations are favored, whereas for strong forces F > Fu, rod-like bundles emerge. In the intermediate force window Fl < F < Fu, bundles with a helical twist can be clearly identified. Applying a field to all monomers yields qualitatively the same effect. This suggests the conclusion that rather flexible polymers under pulling force or field behave effectively like semiflexible polymers without external pull.
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Affiliation(s)
- Dustin Warkotsch
- Institut für Theoretische Physik, Universität Leipzig, IPF 231101, 04081 Leipzig, Germany.
| | - Henrik Christiansen
- Institut für Theoretische Physik, Universität Leipzig, IPF 231101, 04081 Leipzig, Germany.
| | - Johannes Zierenberg
- Max Planck Institute for Dynamics and Self-Organization, Am Fassberg 17, 37077 Göttingen, Germany.
| | - Wolfhard Janke
- Institut für Theoretische Physik, Universität Leipzig, IPF 231101, 04081 Leipzig, Germany.
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Angelescu DG. Molecular modeling of the carbohydrate corona formation on a polyvinyl chloride nanoparticle and its impact on the adhesion to lipid bilayers. J Chem Phys 2024; 160:144901. [PMID: 38591687 DOI: 10.1063/5.0198254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Accepted: 03/21/2024] [Indexed: 04/10/2024] Open
Abstract
The pervasive presence of nanoplastics (NPs) in the environment has gained increasing attention due to their accumulation in living organisms. These emerging contaminants inevitably interact with extracellular polymeric substances along respiratory or gastrointestinal tracts, and diverse organic coating on the surface of NPs, known as bio- or eco-corona, is formed. Although its impact on altering the NP properties and potential cell internalization has been extensively examined, studies on its role in NP partitioning in the cell membrane are elusive yet. In this work, molecular dynamics is used to investigate the formation of chitosan (CT) corona centered on a polyvinyl chloride (PVC) nanoparticle and the uptake of the resulting complex onto lipid membranes. Coarse-grained models compatible with the newly developed Martini 3.0 force field are implemented for the two polymers employing the atomistic properties as targets in the parameterization. The reliability of the coarse-grained polymer models is demonstrated by reproducing the structural properties of the PVC melt and of solvated CT strands, as well as by determining the conformation adopted by the latter at the NP surface. Results show that the spontaneous binding of CT chains of high and intermediate protonation degrees led to the formation of soft and hard corona that modulates the interaction of PVC core with model membranes. The structural changes of the corona adsorbed at the lipid-water interface enable a subsequent transfer of the NP to the center of the saturated lipid membranes and a complete or partial transition to a snorkel conformation depending on the hydrophilic/hydrophobic balance in the CT-PVC complex. Overall, the computational investigation of the coarse-grained model system provides implications for understanding how the eco-corona development influences the uptake and implicit toxicology of NPs.
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Affiliation(s)
- Daniel G Angelescu
- Romanian Academy, "Ilie Murgulescu" Institute of Physical Chemistry, Splaiul Independentei 202, 060021 Bucharest, Romania
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