Rheological And Photoresponsive Properties In The Mixtures Of Hydrophobically Modified Poly(Sodium Acrylate) And Surfactant

Photorheological fluid is one of smart fluids, which changes rheological properties under the stimulation of light with specific wavelength. Therefore, it has important potential applications in microfluidic devices, light control switches, optical storage materials and molecular self-assembly aspect.Excellent photoresponsive fluids must have two ways of performance at the same time, namely excellent mechanical properties (rheological properties) and sensitive response to external stimulation from light, and the two functions must be synergy in one. On this basis, we proposed "component assembly" idea to construct a photoresponsive fluid, namely selected dodecyl(C12)-modified poly(sodium acrylate) HMPANa as the rheological component and surfactant CnTAB micelle as the light-control component. Lastly, photorheological fluid HMPANa/CnTAB (n=12,16) 1α-CD/ADA was successfully prepared and the "component assembly" idea to construct a lightresponsive fluid was confirmed. The main results are summarized as follows:1. The properties of hydrophobically polymer HMPANa solution and the rheological properties of the mixed system with surfactant C16TAB were investigated. Meanwhile, the variation and mechanism of the rheological properties for the mixed system were analysed. The results show that HMPANa/C16TAB system is suitable for the basic system of the photorheological fluid.2. Light sensitive elements were added to the HMPANa/CigTAB mixed system in order that C16 TAB micelle was photoresponsive. The effects of different photosensitizers were discussed in detail. Experimental results suggest that a pair of host-guest a-CD/ADA is screened as the photosensitive element. Photorheological fluid HMPANa/C16TAB/a-CD/ADA is preliminarly determined.3. Photoresponsive fluid HMPANa/C16TAB/a-CD/ADA was prepared and the effects of the various components content to the rheology in the system were systematically investigated. By comparison, it is concluded that the system 5 g.L-1 HMPANa/0.6 mmol.L-1C16TAB/4.5 mmol.L-1α-CD/0.6 mmol.L-1ADA not only is better photoresponsive, but also has better reversibility.4. The influence of surfactant CnTAB (n= 12,16) alkyl chain length to the rheology for the photoresponsive fluid has been studied. This observation indicates that the length of alkyl chain affects its interactions with other molecules in the mixture. However, it has no significant effect to the photoresponsive rheology of the system.5. The interactions among the various components of the photoresponsive fluid HMPANa/CnTAB/ot-CD/ADA were analysed based on the above test results, especially the competitiveness of HMPANa alkyl chains, CnTAB alkyl chains, 4,4’-azodibenzoric acid (ADA) with a-CD. The results show that a-CD interacts more favorably with CnTAB alkyl chains than HMPANa alkyl chains. Therefore, added a-CD preferentially interacts with CnTAB alkyl chains. In addition, CnTAB which has longer alkyl chain is much easier to bind with α-CD, so that ADA is more difficult to snatch a-CD from the alkyl chains.