- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
The role of dipole structure and their interaction on the electromechanical and actuation performance of homogeneous silicone dielectric elastomers
摘要： Grafting polar groups onto elastomer chains has proven to be an effective method to achieve high performance homogenous dielectric elastomers (DE). Up to now, there still lacks an in-depth understanding of the effect of structure and content of these grafted dipoles on the electromechanical properties of the modified DE. In this study, three kinds of polar groups including carboxyl (COOH), hydroxyl (OH), and ester (COOCH3) are grafted onto Polymethylvinylsiloxane (PMVS) by using a photochemical thiol-ene reaction to prepare PMVS-COOH, PMVS-OH and PMVS-COOCH3 DE. Three grafting degrees (15%, 50% and 95%) were prepared for each kind of modified PMVS. Interestingly, although the dipolar moment of COOH is higher than that of OH and COOCH3, at the same grafting degree, the dielectric constant of PMVS-OH is much higher than that of PMVS-COOCH3 and PMVS-COOH. At high grafting degree (50% and 95%), the actuated strain at a specific electric field of PMVS-OH is significantly higher than that of PMVS-COOH and PMVS-COOCH3. The actuated train at a 15 kV/mm sharply increases from 0.2% for PMVS to 9.1% for PMVS-OH with the grafting degree of 95%, higher than that of the commercial silicone DE and the new structured silicone DE reported previously. These dielectric, mechanical and actuated properties are affected by the combined effects of moment, mobility and interactions of these dipoles, which have been deeply discussed. The present study provides guidance for the preparation of high-performance homogeneous DE by rational designing the dipolar structure and content.
关键词： Polymethylvinylsiloxane,dipoles,electromechanical properties,thiol-ene click chemistry,dielectric elastomers,actuated strain
更新于2025-09-23 15:23:52
-
A computational model of bio-inspired tunable lenses
摘要： Bio-inspired tunable lenses are composed of soft dielectric elastomer membranes, clear liquids and rigid frames. Being a new type of optical lens, its focus can be adjusted by the applied voltage. For this type of micro-lens to be practically used in real life, the functional relationship between the voltage and the focus needs to be determined, together with the impact of lens parameters such as the pre-stretching of soft dielectric elastomer membranes, the scale and the volume of liquids on this relationship, as well as on the maximum change of lens focus. In this paper, a compact computational model is proposed based on the assumption of homogeneous deformation and application of energy methods. The model results fit well with the experimental data. By using this model, the relationship curve between the applied voltage and the focus has been given, and it has been verified that such lens will not fail in operation. Finally, by analyzing the three parameters of lens, we can also demonstrate that the pre-stretching of dielectric membranes and the scale affect the relationship between the applied voltage and the focus the most, with the volume of liquids having the least impact.
关键词： large deformations,Bio-inspired tunable lenses,dielectric elastomers
更新于2025-09-23 15:21:01
-
Electrically Responsive Materials and Devices Directly Driven by the High Voltage of Triboelectric Nanogenerators
摘要： Smart materials with electrically responsive characteristics and devices relying on different electrostatic effects can be directly driven by triboelectric nanogenerators (TENGs). The open circuit voltage from a TENG can easily reach thousands of volts with a separation distance of a few millimeters and this high output voltage can be used to effectively drive or control some devices with high internal resistance. This kind of combination is the most straightforward way for achieving a self-powered smart system. Hence, a detailed survey of electrically responsive materials and devices that can be successfully combined with TENG is summarized, including dielectric elastomers, piezoelectric materials, ferroelectric materials, electrostatic manipulators, electrostatic air cleaners, and field emission and mass spectrometers. Moreover, key factors in determining suitable materials or devices to work with TENG are clarified and an in-depth discussion of the current challenges related to these combined systems is provided. With the cost-effectiveness and simple manufacturing process, these TENG-based composite systems have great application prospects in the field of smart mechanics, human–machine interaction systems, intelligent storage systems, self-powered microfluidic chips, portable mass spectrometers, and so on.
关键词： piezoelectric materials,mass spectrometers,electrostatic air cleaners,dielectric elastomers,electrically responsive materials,self-powered systems,field emission,electrostatic manipulators,triboelectric nanogenerators,ferroelectric materials
更新于2025-09-10 09:29:36
-
Effect of crosslinks, entanglements, and chain extensibilities on dynamic electromechanical instability of dielectric elastomers
摘要： Dynamic electromechanical instability (EMI) can affect the actuation performance of dielectric elastomers (DEs). This letter develops a theoretical framework to investigate the dynamic EMI of DEs with diverse crosslinks, entanglements, and chain extensibilities under a step voltage and equal biaxial pre-stresses. Based on the work-energy principle combining the EMI condition, the dynamic instability parameters at transition state between the stable and instable states are determined. At the small pre-stress, weak crosslinks or strong entanglements contribute to achieving a high actuation stretch ratio. When the pre-stress further increases, the DE with strong entanglements is prone to the dynamic EMI, and the variation in the dynamic instability actuation stretch ratio with the level of crosslinks is non-monotonic, which forms a peak. Moreover, as the level of chain extensibilities reduces, the dynamic instability actuation stretch ratio increases, and the enhancement effect can be significant at the large pre-stress. These results can help optimize the dynamic DE to obtain a stable oscillation without the dynamic EMI or utilize dynamic EMI to achieve a dramatic deformation.
关键词： Entanglements,Chain extensibilities,Dielectric elastomers,Crosslinks,Dynamic electromechanical instability
更新于2025-09-04 15:30:14