One-Dimensional Swelling of a pH-Dependent Nanostructure Based on ABC Triblock Terpolymers

We present a novel route to prepare pH-dependent nanostructures from highly ordered thin films of poly(styrene)-block-poly(2-vinylpyridine)-block-poly(tert-butyl methacrylate) triblock terpolymers. Using a polymer-analogous reaction, we modify the chemical nature of the block components without altering the overall microdomain structure. In particular, we perform an acid-catalyzed hydrolysis of the poly(tert-butyl methacrylate) block to poly(methacrylic acid) in a microphase-separated perforated lamella (PL) structure. Scanning force microscopy in an aqueous environment is used to follow structural changes of the PL phase as a function of the pH value. Due to the particular microdomain structure of the precursor triblock terpolymer, an almost perfect one-dimensional swelling of the films is observed with increasing pH.