Preparation of Soft Shape Memory Polymer and Its Application as a Compliant Thermal‐Triggered Gripper

Abstract

AbstractA shape memory polymer always experiences a large modulus change above and below its transition temperature. Cooling down below its transition temperature leads to a sharp modulus increase. That helps the temporary shape fixing, however, it also gives the material noncompliant character, which may be a harmful factor in some applications. In this work, an approach is proposed to prepare a soft shape memory polymer with low modulus even at low temperature. The realization of this polymer depends on the mixing of two raw materials through nano‐latex blending technique. By using styrene, meth acrylate, and n‐butyl acrylate as model monomer, two kinds of core–shell latexes are synthesized, which have a triblock structure as polystyrene‐b‐poly (styrene‐co‐meth acrylate)‐b‐polystyrene and polystyrene‐b‐poly (n‐butyl acrylate)‐b‐polystyrene, respectively. Blending in the unit of nano‐latex particle helps them mixing very homogenously and forms co‐continuous morphology. The blending ratio is tuned to prepare materials with modulus lower than 50 MPa at 20 °C, meanwhile with excellent shape memory performance. Such a soft shape memory polymer shows unique advantage as a compliant thermal‐triggered gripper to stick and place objects.