Colloidal Crystals in Latex Films: Rubbery Opals

Abstract

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.

Surfactant‐Free Emulsion Polymerization of Various Methacrylates: Towards Monodisperse Colloids for Polymer Opals

“…[5,6] Three-dimensional photonic crystals for the visible range are mostly prepared by the self-assembly of preformed objects. The constituent beads are SiO 2 or, more recently, polymer colloids of some hundred nanometers in diameter, which are crystallized into a face centered cubic lattice and dried (empty interstices).…”

“…Relationship between monomer concentration and particle size for PMMA(6,12 and 30 mmol/l initiator), PTFEMA (12 mmol/l) and PtBMA (12 mmol/l).…”

High Frequency Acoustics in Colloid-Based Meso- and Nanostructures by Spontaneous Brillouin Light Scattering

“…The synthesis of the initial core-shell particles was performed by my coworker Diana Kiefer at DKI, Darmstadt and is briefly described here: [17,67,167] The synthesis starts with the preparation of the silica core following the Stöber process and subsequent step-by-step growing as described in Section 4.4. The silica core's surface was functionalized by acryl silanes on which a thin (∼5 nm) PMMA interlayer was crafted by emulsion polymerisation of methy methacrylate (MMA) together with some allyl methacrylate (ALMA) monomer, using sodium dodecylsulfate (SDS) as an emulsifier and ammonium peroxodisulfate and sodium dithionite as a redox initiator system.…”

Architecture of Polymeric Superstructures Constructed by Mesoscopically Ordered Cubic Lattices

“…Goetz and Hellmann [106] prepared core-shell latex particles of PS/PMMA/poly(ethyl acrylate) (PEA) by stepwise emulsion polymerization. The sphere diameter was approximately 200 nm.…”