Wettability of the morphologically and compositionally varied surfaces prepared from blends of well ordered comb-like polymer and polystyrene

Abstract

Phase-separated surfaces of blends of polystyrene (PS) and well ordered comb-like polymer, poly[(oxy(decylsulfonylmethyl)ethylene)] (CH 3-10SE), were prepared by spin casting polymer mixtures. Various surface morphologies, such as holes, islands, connected islands and pillars, were prepared by changing the blend compositions. Due to the influence of the CH 3-10SE domain with a well ordered molecular conformation, a very low energy surface (≈22 mN/m) was created, which is close to the value of the pure polymer (≈20 mN/m), even when the blends contained only 20 wt.% of the pure polymer. Furthermore, by selective etching the PS domain in the blend surfaces, the advancing contact angles of water and n-hexadecane were highly increased from 113.5° and 43.2° for the pure CH 3-10SE surface to 133.3° and 67.2° for the CH 3-10SE structural surfaces with holes prepared using the solvent etching method, respectively. The result of the water advancing contact angles measured on the samples immersed in water over 20 days showed that the film stability of CH 3-10SE could be improved considerably by even adding small amounts of PS.