Anisotropic shape-memory elastomeric composites: Fabrication and testing

Anisotropic shape-memory elastomeric composites (A-SMEC) are fabricated by infiltrating an aligned electrospun fibrous web with an elastomer, and curing. Mechanical testing proves strong anisotropy in Young's modulus (E_Y), strain-to-failure (Ïμ_f), and yield stress (σ_y) observed with averages of E_Y = 48.4 and 4.0 MPa, Ïμ_f = 198 and 351%, and σ_y = 4.6 and 0.9 MPa for longitudinal and transverse loading directions, with respect to the fibrous web's orientation. Shape-memory (SM) characterization reveals modest anisotropy in the shape fixing ratios (R_f), yet seemingly isotropic shape recovery (R_r) nearing completeness. Such soft, anisotropic materials may be used in laminated composite elastomers. Anisotropic shape-memory elastomeric composites are prepared by electrospinning a web of oriented fibers, followed by the infiltration, and cure of a silicone matrix. The mechanical properties of the composites are found to be strongly anisotropic in a manner similar to bat wing membranes. Shape-memory testing reveals a dependence of the strain-fixing degree on the orientation direction, and excellent shape recovery in all directions.