Polysulfone-graft-poly(tert-butyl acrylate) or PSf-g-PtBA samples were prepared by reacting lithiated Udel polysulfone (PSf) in THF at -78 degreesC with bromine-end-functionalized poly(tert-butyl acrylate) or PtBA-Br. In bulk, the PtBA branches segregated from the PSf backbone to form nanometer-sized domains. The PtBA domain shape changed from wormlike to cylindrical and to lamellar as its volume fraction increased from 19.2% to 44%. While the wormlike and cylindrical morphologies lacked long-range order, the alternating PtBA and PSf lamellae were packed regularly. The PtBA domains in such graft copolymer films could be hydrolyzed to yield poly(acrylic acid) or PAA chains without affecting film integrity. After PtBA hydrolysis, a sample with a PtBA volume fraction of 38% showed iridescence or a 1-D photonic stop band at similar to450 nm in basic water. The iridescence could be turned off and on by cycling pH between 2 and 10, for example.