Figure 3. Analysis of the influence of nano wrinkled structure on the photothermal performance. (a) Comparison of original structure, porous structure and nano-wrinkled structure. (b-g) Comparison of micromorphology of nano-wrinkled and non-nanowrinkled structures (The inset images are comparison of photothermal performance of nano-wrinkled and non-nanowrinkled structures after 5min 1 sunlight irradiation.). (b) The photothermal membrane treated by solvent of tetrahydrofuran. (c) The photothermal membrane treated by solvent of acetone. (d) Acetone treatment, drying and then treated with tetrahydrofuran containing CS/MWCNTs. (e) Treatment with tetrahydrofuran containing CS/MWCNTs, drying and then acetone treatment. (f) Acetone treatment and then treatment with tetrahydrofuran containing CS/MWCNTs. (g) Nano-wrinkled structure in this study. (h) The photothermal comparison of membranes before and after 5min sunlight irradiation by the 5 solvent-induced recrystallization in b-g. (i) The BET of photothermal membranes.