Strain-Responsive Structural Colored Elastomers by Fixing Colloidal Crystal Assembly

• Published in: Langmuir Vol. 29; no. 45; pp. 13951 - 13957
• Main Authors: Ito, Tatsunori, Katsura, Chihiro, Sugimoto, Hideki, Nakanishi, Eiji, Inomata, Katsuhiro
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 12.11.2013
• Subjects: Chemistry; Colloidal state and disperse state; Exact sciences and technology; General and physical chemistry; Physical and chemical studies. Granulometry. Electrokinetic phenomena; Deformation; Swelling; Film; Crystals; Elastomer; Elasticity; Polymer; Soap; Wavelength; Absorption spectrum; Thickness; Random copolymer; Emulsion polymerization; Monodispersed particle; Rubber; Monomer; Methyl methacrylate; Structure; Colloid particle
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/la4030266

Colloidal crystal assembly film was prepared by using monodispersed colloidal particles of cross-linked random copolymer of methyl methacrylate and ethyl acrylate prepared by soap-free emulsion polymerization. The colloidal crystal film exhibited structural color when swollen with ethyl acrylate monomer. The structural color was maintained even after polymerization of the swelling monomer and cross-linker, suggesting the colloidal crystalline order was successfully fixed and embedded in the matrix of poly(ethyl acrylate) elastomer. Stretching deformation of the structural colored elastomer induced a sensitive change to shorter wavelength color. Peak wavelength of the UV–vis absorption spectrum of the stretched elastomer revealed an excellent proportional relationship with film thickness. In the swollen colloidal crystal film, ethyl acrylate was absorbed in the colloidal particle; therefore, poly(ethyl acrylate) chain should be penetrating into the colloidal particle after the polymerization of the matrix elastomer. This interpenetrated polymer network structure was considered to be effective for the rubber-like elasticity and sensitive strain-responsive color-changing phenomena of the structural colored elastomer.