Polyimides are representatives of high-performance polymers. One member of the family (PI-2730 series) has found application as a photodefinable negative resist, allowing the surface chemistry to be altered through UV exposure. The evolution in lateral differentiation arising from masking and subsequent exposure has been investigated. Analysis showed that exposure resulted in increasing hydrophilicity, as well as shrinkage of the exposed areas. A particular focus of the study has been on the effect of lateral chemical differentiation on selective adsorption of functionalised beads, and on arrays of precipitate structures. (C) 2004 Elsevier B.V. All rights reserved.