Structuring of polystyrene surface via swelling–freezing drying in a binary solvent solution

Abstract

Here we fabricated porous polystyrene (PS) plates via a two-step process: swelling process and freezing process. An aqueous solution containing tetrahydrofuran (THF) was used in the swelling process and liquid nitrogen for the freezing process. Two types of the structures as sponge structure and pore structure were found by adjusting THF content in the solution, swelling time and freezing time, respectively. The pore size was mainly in the range of 1–4 μm with narrow size distribution. The surface hydrophilicity changed slightly with THF content and the swelling time. However, the absorption properties of PS plates in either water or oil increased with THF content in the solution from 70 to 80 wt%, the swelling time from 5 to 10 min, and the freezing time from 1 to 1.5 h.