The conformational behavior and unperturbed dimensions of polysulfone and chloromethylated polysulfone with different degrees of substitution were investigated by viscometry in N,N-dimethylformamide; we intended to use these results with more complicated structures with different properties and applications. The effects of concentration and temperature on the coil densities and dimensions and of chlorine content on the unperturbed dimension parameters are discussed. (c) 2006 Wiley Periodicals, Inc.