Effect of the charge on the morphology of sodium salt form of the randomly sulfonated polystyrene ionomer cast onto silicon wafers.

Author(s): Yu JA, Oh SH, Kim JS

Affiliation(s): Department of Science Education, Chosun University, Gwangju 501-759, Korea.

Publication date & source: 2007-11, J Nanosci Nanotechnol., 7(11):4025-8.

Publication type: Research Support, Non-U.S. Gov't

The morphology of the sodium salt form of randomly copolymerized polystyrene sulfonate (Na-PSS) in water/THF(99/1 v/v) cast onto silicon wafers, was studied by using scanning electron microscope (SEM). The contents of the sulfonate repeat units in Na-PSS were 1.1, 2.4, 4.6, 10.8, and 15.6 mol%. Based on the observed SEM images, the morphology of the Na-PSS changed with increasing ionic group content. For 1.1 and 2.4 mol%, sphere-shaped aggregates were formed with average sizes of 90 nm and of 77 nm, respectively. For 4.6 mol% and 10.8 mol%, 20-30 nm-sized aggregates were close-packed and fused together, resulting a surface with large roughness and ca. 10 nm-sized pores were formed. As the mol% increased to 15.6, the surface became smoother and flat films were formed.