The Preparation And Spatiotemporal Dynamics Of Photoresponsive Self-oscillating Gels

Light stimulus-responsive gel system is studied in this thesis through investigating the performance of Ru coordinate catalysts in BZ reaction, the microstructure of gels and chemical kinetics of the system coupling BZ reaction with gel behaviors. The skeleton of gel is consisted of monomer and Ru coordinate catalyst, Which is determining the diffudion amd reaction rate of the system. The Ru coordinate catalyst as a coupling bradge of BZ reaction with gel, is a motor of the system Coverting chemical energy to mechanical energy, in which the properties of Ru catalyst determines the efficiency of energy conversion. The study of chemical behaviors of gel provides the mentality of designing on intelligent meterials and promotes the potential applications of BZ gel on biomimetic science and quality transmission.Firstly, Ru(bpy)32+, Ru(phen)32+ and Ru(phen-NO2)32+ were synthesized and properties of three catalysts were observed through electrochemical cyclic voltammetry within different concentration of nitric acid. Swelling shrinkage volume ratio of gels by grafing different catalysts were investigated under the different temperature. The microstructure of gels containing the N-Isopropylacrylamide(NIPAAm), acrylamide(PAAm) and methyl acrylamide(MPAAm) were scaned by SEM. The results of the observations shows that Ru(bpy)32+ could stably existed without decomposition in strong acid medium. The electrode potential is bigger than other two type of catalysts. Its different valence state has different colour and the propotion of expansion to contraction is larger. The microstructure of the gel containing NIPAAm as the main monomer is porous, which is liable for the diffusion of reaction solution.The effect of light on the BZ gel containing Ru(bpy)32+ as catalyst was studied. The frequency of BZ gel is related with the intensity of light and swelling shrinkage ratio of gel. The curve of frequency of BZ gel is composed of two stage periods. The first one is induction period within 1.5 h, in which the frequency and intensity of gel is random ascribed on the unable of BZ oscillating reaction. The second region is the stable stage during 8 to 9.5 hours, in which the frequency of BZ gel firstly increased to a highest stable plat, then decreased as the light intensity increasing. The increasing region is induced region and another region is inhibited region. The reaction frequency of BZ gel is higher in the week and medium light intensity than that in high light intensity.The different light intensity could drive the movement of BZ gel and the movement curve visus time could divide into three different stages: initial stage, accelerating stage and stable stage, which is related to the intensity of light. The initial stage was determinated by the induction frequency. The acceleration stage is driven by the different frequency at both ends, which also is the most important stage of the gel movement. There are no changes on stable stage.