Soft, Tough, and Thermally Conductive Elastomer Composites\nby Constructing a Curled Conformation

Abstract

Filled\nelastomer composites have gained significant attention due\nto their ability to undergo large-strain reversible deformations with\nminimal force. However, achieving the desired functionality, such\nas high thermal conductivity, often requires ultrahigh filler loadings\n(above 50%). Unfortunately, excessive filler loading compromises the\nsoftness and toughness of the composites due to the prevalence of\ntrapped entanglements. To address this challenge, a simple solvent-thermal\ndesign strategy is reported to optimize the balance among Young’s\nmodulus, stretchability, and toughness in highly filled elastomer\ncomposites. This is realized by the curled conformation formed by\nthe disentangling of the excessively entangled polymer chains and\nby better mixing of the BN filler and the polymer matrix. The released\ntrapped entanglement can effectively reduce the Young’s modulus\n(2.80 MPa) of the C-PDMS/60 wt % BN elastomer composites, and the\nstrong unfolding and stretching ability of the curled conformation\nalso endows it with excellent stretchability (∼492%), thus\nachieving high toughness (∼2.80 MJ m^–3).\nAdditionally, the better mixing ability allows the C-PDMS/60 wt %\nBN elastomer composites to be compounded with the high BN filler loading\n(60 wt %), thus achieving high thermal conductivity (1.65 W m^–1 K^–1). The comprehensive performance\nof the C-PDMS/60 wt % BN demonstrates remarkable advancements in highly\nfilled elastomer composites. Leveraging these favorable characteristics,\nthe curled PDMS/BN elastomer composites can serve as effective thermal\ninterface materials for efficient heat dissipation and hold great\npotential for applications in the field of flexible electronics.