Controlled preparation of nanometer-sized supramolecular cylinders of poly(ethylene oxide) embedded in methacrylate matrices

Semi-interpenetrating networks of poly(ethylene oxide) (PEO) and highly cro sslinked poly(methacrylate)s were generated from solutions of PEO in mixtur es of methacrylate monomers and dimethacrylate crosslinkers. The deep quenc hing of the solutions into the unstable region resulted in microphase separ ation via a spinodal decomposition mechanism. Through the crystallization o f the PEO inside the polymer-rich phase, the domain size was reduced below the Cahn-Hilliard limit. The microstructure was permanently preserved by su bsequent. UV-initiated polymerization of the monomers well below the PEO me lting temperature. The semi-interpenetrating networks were characterized by differential scanning calorimetry, small-angle X-ray scattering, NMR spin- diffusion measurements, and electron microscopy. Morphologies based on netw orks of cylindrical PEO aggregates with diameters of 10 +/- 2 nm were obser ved, nearly independent of the molecular weight of the used PEG. (C) 2000 J ohn Wiley & Sons, Inc.