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Colloidal Crystals in Latex Films: Rubbery Opals
Author(s) -
Ruhl Tilmann,
Hellmann Goetz P.
Publication year - 2001
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/1521-3935(20011201)202:18<3502::aid-macp3502>3.0.co;2-6
Subject(s) - materials science , crystallinity , composite material , elastomer , thermoplastic elastomer , crystallization , transmission electron microscopy , polymer , opacity , copolymer , chemical engineering , optics , nanotechnology , physics , engineering
Elastomeric films were prepared, by uniaxial compression, from core‐shell latex particles with a rigid thermoplastic core and a soft elastomeric shell. The films are rubbery, yet well ordered. The latex spheres form a fcc lattice, the 111 plane of which is oriented parallel to the film plane. This colloidal crystallinity is also found in opals. The films are colored due to selective reflection of the light wavelength corresponding to the lattice spacing, but they are not opaque. The crystallization process is surprisingly simple and fast because the core‐shell latex spheres flow in the melt practically like a regular polymer melt. Under uniaxial compression, this flowing melt deposits crystalline layers of the latex spheres along the plates of the press. The order in the films was characterized with transmission electron microscopy and UV spectroscopy. Deformation of the films results in a shift of the reflected light wavelength.