Study Of Bio-chromism Mechanism And Biomimetic Thin Films

Based on the needs of selfadapting changing color camouflage in military affairs camouflage field, in this paper, changing color mechanism of anole is studied and simulated using lattice image array, transparence glass plate superposing and computer simulation on the basis of addition color mixing and subtraction color mixing. The three kinds of color of forest, desert and earthhas have been simulated. Results show that color mechanism of anole is addition color mixing, and becomes the base of following studying.In order to realize bionics of anole, we prepare ordered mosoporous to simulate the structure of cell, and put photochroism molecules which simulates the coloring matter into mosoporous. By controlling the size of mosoporous and the quantity of photochroism molecules, we can realize bionics of anole. Synchronously, using different kinds ofphotochroism molecules has been explored elementarily.In the process of changing color mechanism biomimetic, in order to prepare wellbihaved ordered mesoporous silica thin films, evaporation-induced self-assembly (EISA) co-condensation is used. The amino-functionalized mesoporous silica thin films have been directly synthesized by co-condensation of tetraethoxysilane (TEOS) and 3-aminopropyltriethoxysilane (APTES) in the presence of cationic (CH₃(CH₂)₁₅N+ (CH₃)₃Br-(CTAB), nonionic C₁₆H₃₃(OCH₂CH₂)₁₀OH (Brij-56), or triblock copolymer (H(OCH₂CH₂)₂₀(OCH(CH₃)CH₂)₇₀(OCH₂CH₂)₂₀)OH) (P123) surfactant species under acidic conditions by sol-gel dip-coating. Using different surfactants, prepared hybrid mesoporous silica thin films have different pore diameter and phase structure (2D hexagonal and 3D cubic). The mesoporous materials with amino-groups in the pores wall or within the frameworks can expand the applications. Great interests have been focused on the synthesis of processing conditions and the influence of the structural order. The structure of the materials is characterized by SEM, TEM, and XRD, of which analytic results indicate that the amino-functionalized mesoporous silica thin films are continuous, crack-free, and highly ordered 2D hexagonal and 3D cubic. The Keggin-type molybdphosphoric acid (PMo) is incorporated into the mesoporous silica thin films with amino-groups by wetness impregnation, and the PMo/silica mesoporous composite thin films are obtained. The results of TEM, XRD and FTIR indicate the PMo molecules maintain Keggin structure and are homogeneously distributed inside mesoporores. The photochromic mechanism of the composite thin films is studied by Ultraviolet-visible (UV-vis), electron spin resonance (ESR) and X-ray photoelectron spectroscopy (XPS) spectra. It is shown that intervalence charge transfer (IVCT) and ligand-to-metal charge transfer (LMCT) are the main reason of photochromism. PMo anions interact strongly with amino-groups of the mesoporous suface via hydrogen bond and electrostatic force. After ultraviolet irradiation, the charge transfer occurs by reduction of heteropolyanions accompanying the formation of heteropolyblues with multivalence Mo (â…¥,â…¤), and the bleaching process of composite thin films is closely related to the presence of oxygen. Based on the results above, the assembly of PMo particles and the efficiency of photochroism are chosen as our objects for investigation, which has prodigious innovation.The paper combines bionics technology with military camouflage and provide a new way for military camouflage, and photochroism mosoporous thin films can adapt to the characteristics of modern war quite well. The results above expand the investigation and application areas and offer the theoretic and practical basis for the amino-functionalized mesoporous silica thin films, especially, the special materials have extensive application foreground not only in photochromism, photosensitive switch and information-storage, but also in military camouflage.