Largely improved electromechanical properties of thermoplastic polyurethane dielectric elastomer by carbon nanospheres

Abstract

Carbon nanospheres (CNS) were used as a new conductive filler to improve the electromechanical properties of a thermoplastic polyurethane (TPU) dielectric elastomer (DE). The results showed that CNS with many hydroxyl groups can form hydrogen bonds with TPU molecules, leading to a good dispersion of CNS in the TPU matrix and an improved tensile strength of CNS/TPU composites. More interestingly, CNS disrupted the crystallization of TPU, resulting in the decrease in elastic modulus and hysteresis loss of the composites. The dielectric constant at 1000 Hz increased from 7.1 for pure TPU to 137.3 for the composite with 5 wt% of CNS. The great increase in dielectric constant and the decrease in elastic modulus result in the largely improved actuation strain at low electric field of CNS/TPU composites. In addition, all the as-prepared CNS/TPU composites have a low dielectric loss (<1) at 1000 Hz. Our study provides a simple and effective way to obtain CNS/TPU DE with good mechanical strength and largely improved actuation performance at low electric field.

Interface design for high energy density polymer nanocomposites

“…244 In addition, the nAg particles reduced the space charge through the Coulomb blockade effect. 245 In the case of multi-layer structured composites, the interfacial polarization at the interface between layers plays an important role in the electric and dielectric properties of nanocomposites. For multi-layer structured composites with PVDF-based ferroelectric polymer layers, its enhanced electric displacement often results from the C-F bonds and the spontaneous alignment of dipoles in the crystalline phases of its PVDF based ferroelectric polymer layers (with a low relative permittivity) at a largely enhanced local electric field.…”

Carbon nanotube‐based thermoplastic polyurethane‐poly(methyl methacrylate) nanocomposites for pressure sensing applications

“…). The second reason could be due to the accumulation of large amounts of interfacial charge at the interfaces between PMMA‐CNT and TPU, which is known as the Maxwell–Wagner–Sillars (MW) effect .…”

Plasticized thermoplastic polyurethanes for dielectric elastomers with improved electromechanical actuation

“…Among various elastomers, polyurethanes (PUs) have been proposed as one of the most promising candidates for DEA applications due to their intrinsically high ɛ r , widely tunable mechanical properties, and inexpensive costs. To further improve the electromechanical response of PUs, conductive carbon nanomaterials including carbon nanospheres, carbon nanotubes, and graphene nanosheets have been recently examined as additives to enhance the ɛ r and electromechanical actuation of PUs . These PU composites, though the ɛ r always exhibits extremely high values, can only show limited improvement in electromechanical actuation owing to the poor insulating strength.…”

“…To further improve the electromechanical response of PUs, conductive carbon nanomaterials including carbon nanospheres, carbon nanotubes, and graphene nanosheets have been recently examined as additives to enhance the E r and electromechanical actuation of PUs. [21][22][23] These PU composites, though the E r always exhibits extremely high values, can only show limited improvement in electromechanical actuation owing to the poor insulating strength. Recently, we developed an alternative strategy to enhance the E r of PU by blending organic strong polar azobenzenes.…”