Mechanical anisotropy in compressive-stress shape-programmed liquid crystal elastomers and polymer-dispersed liquid crystal elastomer composites

Abstract Polymer-dispersed liquid crystal elastomer composites (PDLCEs) combine the thermomechanical capabilities of liquid crystal elastomers (LCEs) with the softness of a silicone matrix. The high-temperature persistent glass phase in LCEs allows preservation of the instilled deformations during thermal cycling, leading to reprogrammable shape-memory in both LCEs and PDLCEs. This provides a unique opportunity to study mechanical properties within a single shape-programmed specimen by imposing different mesogen configurations or particle geometries, without the need for repeated synthesis. We specifically focus on compressive programming, which induces transverse mechanical anisotropy and a mesogen configuration with a negative order parameter. Directional stress–strain and thermomechanical tests reveal that, despite the elastic matrix, PDLCEs retain mechanical properties comparable to pure LCEs, highlighting the role of mechanical anisotropy together with inclusion alignment and geometry. The degree of mesogen ordering is evaluated in LCEs, while a modified Halpin–Tsai model captures the mechanical response of PDLCEs.