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Lian Z, Chen D, Li S. Investigation on the Correlation between Dispersion Characteristics at Terahertz Range and Dielectric Permittivity at Low Frequency of Epoxy Resin Nanocomposites. Polymers (Basel) 2022; 14:polym14040827. [PMID: 35215739 PMCID: PMC8879792 DOI: 10.3390/polym14040827] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 02/11/2022] [Accepted: 02/18/2022] [Indexed: 12/10/2022] Open
Abstract
Despite the extensive research on nanocomposites, a fundamental theory on the interface region is still difficult to achieve. In the present paper, we chose epoxy resin and nano-SiO2, nano-SiC, nano-ZnO to prepare three kinds of nanocomposites. The dispersion characteristics at the terahertz range and dielectric permittivity at 1 Hz of epoxy resin-based nanocomposites were investigated. The reduction of the permittivity of nanocomposites at a slight filler concentration was absent at the terahertz range. The measurement results at 1 Hz show that the interaction between nano-SiO2, nano-SiC particles and epoxy resin was strong with the modification of the silane coupling agent. However, the modification of nano-ZnO particles was invalid. The Lorentz harmonic oscillator model was employed to fit the dispersion characteristics. The relevance between the damping constant and the dielectric permittivity at low frequency was established, indicating that the increase in the damping coefficient results from the restriction of the molecular chain motion by the interfacial region. The present results in this paper reveal a bright prospect of terahertz time-domain spectroscopy in establishing the theory of nanocomposite dielectric.
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Affiliation(s)
- Ze Lian
- State Grid Shanxi Electric Power Research Institute, Taiyuan 030001, China;
- State Key Laboratory of Electrical Insulation and Power Equipment, Xi’an Jiaotong University, Xi’an 710049, China;
- Correspondence: or ; Tel.: +86-15333662660
| | - Danyang Chen
- State Grid Shanxi Electric Power Research Institute, Taiyuan 030001, China;
| | - Shengtao Li
- State Key Laboratory of Electrical Insulation and Power Equipment, Xi’an Jiaotong University, Xi’an 710049, China;
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Zeng Z, Mavrona E, Sacré D, Kummer N, Cao J, Müller LAE, Hack E, Zolliker P, Nyström G. Terahertz Birefringent Biomimetic Aerogels Based on Cellulose Nanofibers and Conductive Nanomaterials. ACS NANO 2021; 15:7451-7462. [PMID: 33871983 DOI: 10.1021/acsnano.1c00856] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Biomimetic, lamellar, and highly porous transition-metal carbide (MXene) embedded cellulose nanofiber (CNF) aerogels are assembled by a facile bidirectional freeze-drying approach. The biopolymer aerogels have large-scale, parallel-oriented micrometer-sized pores and show excellent mechanical strength and flexibility, tunable electrical properties, and low densities (2.7-20 mg/cm3). The CNF, MXene, and lamellar pores are efficiently utilized to endow the aerogels with exceptionally high birefringence in the terahertz (THz) regime. Birefringence values as high as 0.09-0.27 at 0.4 THz are achieved, which is comparable to most commercial THz birefringent materials such as liquid crystals, which suffer from fast disintegration, high cost, and complicated preparation processes. Empirical modeling for different MXene contents and an experimental comparison with silver nanowire or carbon nanotube embedded CNF aerogels suggest that the intrinsic conductivity and content of embedded nanomaterials, the aerogel porosity, and the lamellar cell walls can affect the optical properties such as the THz birefringence and absorption. The determination of optical anisotropy in the biopolymer aerogels lays a foundation for further exploration of ultralight, freestanding, and low-cost biomimetic porous architecture-based THz devices.
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Affiliation(s)
- Zhihui Zeng
- Laboratory for Cellulose & Wood Materials, Empa, 8600 Dübendorf, Switzerland
| | - Elena Mavrona
- Laboratory for Transport at Nanoscale Interfaces, Empa, 8600 Dübendorf, Switzerland
| | - Daniel Sacré
- Laboratory for Transport at Nanoscale Interfaces, Empa, 8600 Dübendorf, Switzerland
| | - Nico Kummer
- Laboratory for Cellulose & Wood Materials, Empa, 8600 Dübendorf, Switzerland
- Department of Health Sciences and Technology, ETH Zürich, 8092 Zürich, Switzerland
| | - Jingming Cao
- Laboratory for Transport at Nanoscale Interfaces, Empa, 8600 Dübendorf, Switzerland
| | - Luca A E Müller
- Laboratory for Cellulose & Wood Materials, Empa, 8600 Dübendorf, Switzerland
| | - Erwin Hack
- Laboratory for Transport at Nanoscale Interfaces, Empa, 8600 Dübendorf, Switzerland
| | - Peter Zolliker
- Laboratory for Transport at Nanoscale Interfaces, Empa, 8600 Dübendorf, Switzerland
| | - Gustav Nyström
- Laboratory for Cellulose & Wood Materials, Empa, 8600 Dübendorf, Switzerland
- Department of Health Sciences and Technology, ETH Zürich, 8092 Zürich, Switzerland
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