A new function for thermal phase transition-based polymer actuators: autonomous motion on a surface of constant temperature† †Electronic supplementary information (ESI) available: Additional figures, tables, discussions and experimental information. See DOI: 10.1039/c7sc01792h Click here for additional data file. Click here for additional data file. Click here for additional data file. Click here for additional data file.

Sample preparation. 6 g EVA (containing 18 wt.% of VA, Sigma-Aldrich, Canada) was first dissolved in 50 mL toluene at 80 oC under magnetic stirring to form homogeneous solution, which was then cooled to 55 oC and subsequently added with 0.123 g DCP (dicumyl peroxide, Sigma-Aldrich, Canada) and continuously stirred for 10 min. The above solution was first cast into a petri dish to allow evaporation of the solvent overnight in the hood, then moved to a vacuum oven and dried at 60 oC for 48 hours to remove the residual solvent. The obtained composite containing 2.0 wt.% DCP was cut into particulates and then hot-compressed (170 oC and 2.5 MPa for 10 min, then 190 oC and 3.0 MPa for 10 min, and finally 200 oC and 3.5 MPa for 25 min) and crosslinked (using Carver Laboratory Press, Model C, Fred S. Carver Inc., USA) in metal molds into sheets with desired dimension.