Towards Improved Electromechanical Properties in Soft Silicone Films Using Two-Dimensional Materials

Description

Soft silicone polymers, with their low, tuneable elastic moduli, are promising candidates for dielectric elastomer actuator fabrication, with uses found in artificial muscles and soft robotics. To further increase applicability in such devices, many attempts have been made to enhance the relatively low dielectric constant of silicone through the addition of high-permittivity fillers. For many commonly-used filler materials, improvements in permittivity are observed to the detriment of other key performance parameters, with rigid particles leading to unfavourable elastomer stiffness increases, and conductive particles tending to reduce dielectric breakdown strength.
Platelet fillers have shown great promise for improving electromechanical properties in polymer composites. For example, breakdown field increases were observed in oriented clay platelet-filled polyethylene, with electron transport hindered by the aligned high-aspect ratio particles. Furthermore, low loadings of conductive platelets have increased silicone resistivity due to charge trapping effects. Two-dimensional crystals offer a huge range of ultra-thin nanoplatelets with complementary and often exceptional properties; they may be micron-sized in lateral dimensions, but only a few nanometres thick, and are widely-known for their flexibility. In this work, graphene, a conductive two-dimensional honeycomb carbon lattice, and its insulating analogue, hexagonal boron nitride, are investigated as flexible nanoplatelet fillers in an attempt to improve silicone breakdown strength and permittivity without compromising elastomer softness. Focus is placed on achieving well-dispersed nanoplatelets at low loadings; where necessary, nanoplatelet functionalisation using silane coupling agents is explored, due to compatibility issues.

Period	1 Jul 2025
Event title	13th International Workshop on Silicone-based Polymers
Event type	Conference
Location	Snekkersten, DenmarkShow on map
Degree of Recognition	International