Multifunctional shape-memory foams with highly tunable properties via organo-phase cryo-polymerization
Polymer foams with interconnected open macropores have been widely utilized in industry and our daily lives. Cryo-polymerization is a simple yet efficient method to prepare open porous materials. However, such a technique was in most cases used in an aqueous phase manner to synthesize macroporous hydrogels and material diversity need to be further developed to achieve multi-functions. In this work, we present organo-phase cryo-polymerization as a facile and general method to synthesize acrylate-based shape-memory foams with controllable pore architecture and highly tunable properties including thermo-mechanical behavior and swelling capability. Pore orientation and porosity can also be controlled through manipulating conditions of cryo-polymerization such as freezing routes and monomer concentrations. By varying monomer compositions (methyl methacrylate/butyl acrylate), shape-memory foams with highly tunable transition temperature (Tg from approximately -43 °C to 123 °C) were obtained. Amongst various potential applications, we demonstrate that the shape-memory foams can be programmed into a rather compact form and expand only during the solvent absorption process to allow simultaneous fast and large absorption, an advantage over the intrinsic bulkiness of classical porous absorbents. Poly (lauryl methacrylate) foam was also prepared, which enabled fast absorption of various solvents including gasoline (ADf = 10.2 g/g).