Study Of Shape Memory Of Porous Polycaprolactone And Its Composites With Graphene Oxide Driven By Solvent

In this paper,porous polycaprolactone(PCL)and its composites with graphene oxideis(GO)were fabricated by the state transition from liquid to solid of PCL solution or PCL/GO solution at room temperature.The microstructure,crystallization and mechanical properties of porous PCL and PCL/GO composites were investigated by various characterization methods.The shape memory properties of PCL/GO composites driven by ethyl acetate were studied.The factors affecting the shape memory performance are also discussed.Besides,the mechanism of quick chemo-responsive shape recovery is proposed,and the mechanism is further explained by programming experiments by solvent and shape recovery driven by the vapor of ethyl acetate.The experimental results show that GO not only made the pore structure of PCL regular and distributed uniformly,but also improved its crystallization and mechanical properties.There are several factors that influence the shape memory performances of PCL and its composites,including the size of the material,the content of GO,the number of recovery cycles and mixed solvent.The PCL and its composite with GO(1.0wt%)with the aspect ratio of 50:5 driven by ethyl acetate can recover in one second.The quick chemo-responsive shape recovery is ascribed to the wrinkle effect which is produced by the rapid release of the energy stored at the deformed location during programming.The quick emergence of wrinkle is related with the connected micrometer-level porous structures composed by twisted nanometer schistose structures and the formation of intermolecular hydrogen bonds between PCL and the ester group of the solvent.The wrinkle induced shape recovery is much different to the plasticization effect or swelling effect in common chemo-responsive shape memory polymers.It not only enriches the knowledge of chemo-responsive SME,but also expands the potential applications of shape memory polymers such as fast solvent-responsive sensors.