COMPOSITES SCIENCE AND TECHNOLOGY
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2020
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IF 7.094
Daomin Min,Haozhe Cui,Yali Hai,Pengxin Li,Zhaoliang Xing,Chong Zhang,Shengtao Li
Interfacial regions formed by incorporating a certain percentage of nanofillers into a polymer matrix can impact on the motion of molecular groups, chain units or chain segments, and alter molecular chain network dynamics, which is regarded as a key factor to achieve a finer degree control of dielectric properties of polymer nanocomposites . It is of interest to investigate the molecular chain motion behavior at interfacial regions with the incorporation of nanofillers. Epoxy resin/polyhedral oligomeric silsesquioxane (EP/POSS) nanocomposites are fabricated and the observations of morphology structure and chemical elements indicate that POSS nanofillers are well dispersed in the matrix. Differential scanning calorimeter , dynamic thermomechanical analysis, and dielectric relaxation spectroscopy are measured to analyze the effect of nanodoping on the motion properties of molecular chain units and chain segments that satisfy the Arrhenius and Vogel-Fulcher-Tammann equations respectively. The thicknesses of interfacial regions between POSS nanofillers and EP matrix are estimated from dielectric spectra and effective relative permittivity simulations, which are around several nanometers and decrease with the increment in the nanofiller content. In addition, the dielectric spectra scaling analysis indicates that the motion of small chain units can be hindered in interfacial regions and be tuned simultaneously by the variations of molecular chain network structure and dynamics. Nevertheless, the thin interfacial regions cannot effectively restrict the orientation of long molecular chain segments during the glass transition process. The variation of chain segment orientation behavior is ascribed to the interactions among molecular chains tuned by the binding effect of POSS nanofillers.
研究领域:
材料科学
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高分子化学
✓ 已验证
产品关联
DOI
高影响因子
Surfaces and Interfaces
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2023
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IF 6.2
Ziwei Gao,Shurao Cai,Daomin Min,Yutao Hao,Minzun Ji,Qingzhou Wu,Shengtao Li,Wenfeng Liu
Polymer dielectric materials are crucial for storage devices in power and electronic systems, as well as electric vehicles, due to their high energy density and fast discharge rates. Polymer nanocomposites (PNCs) possess superb electrical and energy storage properties, making them highly promising as next-generation thin-film dielectrics for energy storage. The excellent performance of PNCs derive from the interfacial region introduced by nano-doping. However, the current measurement equipment and technology make it difficult to accurately obtain the mesoscopic scale distribution characteristics of the conductivity of the interfacial region, and are also impossible to clarify the formation mechanism of deep traps in the interfacial region. We employed high-throughput simulation and experiment to investigate the mesoscopic conductivity and trap distribution properties of the interfacial region in PNCs. Furthermore, we developed a three-dimensional mesoscopic conductivity distribution simulation model of PNCs containing polymer matrix, nanoparticles, and interfacial region. The interfacial region size and conductivity distribution of the PNCs were determined by comparing with the experimental results, and the mesoscopic distribution characteristics of the interfacial traps in PNCs were obtained. It is proved that the nanofillers form a condensed structure with high order and compactness by restraining the movement of molecular chains, which deepens the trap energy in the interfacial region and restricts the free volume expansion. This results in the formation of interfacial regions with low conductivity, contributing to enhancing energy storage performance.
研究领域:
材料科学
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电气工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Physical Chemistry C
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2016
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IF 4.509
Simin Peng,Bin Dang,Yao Zhou,Jun Hu,Jinliang He
The interfacial region between a nanoparticle and the polymer matrix is considered to have an important effect on the properties of nanocomposites. In this experimental study, the tuning effects of surface-modified TiO2 nanoparticles on the aggregation structure and trapping property of the nanocomposites are investigated. The addition of TiO2 nanoparticles increases the number of spherulites and decreases their sizes. It is also found that TiO2 nanoparticles can suppress the mobility of chain segments in the interfacial region, suppress crystallization, and reduce the crystallinity, depending on the surface modification and loading levels of nanoparticles. On the basis of the conclusions, the model of a spherulite and the interface is established and the trap distribution of the interface is analyzed according to the results of TSC measurements. It is assumed that there is a strong correlation between traps and the charge transport of nanocomposites, and the mechanism of charge transport is discussed with respect to the results of the volume conductivity measurement. It is believed that this study would provide an important hint to the research of the interface between nanoparticles and the polymer matrix in future research.
研究领域:
材料科学
·
高分子物理
✓ 已验证
产品关联
DOI
高影响因子
Materials Today Energy
·
2023
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IF 9.3
Daomin Min,Yanan Duan,Ziwei Gao,Yutao Hao,Xiaofan Song,Shihang Wang,Qingzhou Wu,Wenfeng Liu
Polymer nanocomposites (PNCs) are important energy storage dielectrics for capacitors. However, the lack of quantitative research on the properties of mesoscopic scale conductivity, traps, and Young's modulus in interfacial regions between polyetherimide and nanofillers results in an unclear understanding of the relation between the structure and properties. Polyetherimide/Al 2 O 3 PNCs are prepared by in-situ polymerization, and the dielectric, thermal, and mechanical properties are measured. The experiments show that the film doped with 3 wt% nanofillers has the highest resistivity, Young's modulus, breakdown strength , and energy storage density. Then, the mesoscale distributions of the conductivity and Young's modulus in interfacial regions are solved as the inversion problem of electric and stress fields, and the macroscopic conductivity and Young's modulus of PNCs are obtained by high-throughput simulations. The conductivity, trap, and Young's modulus distributions are obtained by comparing the simulation and experimental results. It shows that the molecular chains in interfacial regions are bounded by nanofillers to form a tighter aggregated structure, hindering the molecular motion. Accordingly, the charge transport between molecular chains slows down, the trap energy increases and the conductivity decreases. The tighter aggregated structure makes PNCs have higher breakdown strength, energy storage density, and lower energy loss.
研究领域:
材料科学
·
电气工程
·
机械工程
·
高分子科学
✓ 已验证
产品关联
DOI
高影响因子
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