Study On Polymer/Inorganic Composite Intelligent Hydrogel And Its Device

Recently, the development of polymer/inorganic nano-composite hydrogel devices has attracted more and more attention, such as cell scaffold, self-folding film, bionic actuator etc. With the development of intelligent hydrogel devices, the researchers require a high-performanced device, such as the controllable and more complex responsive deformation of hydrogel and the controllable motion of hydrogel and multiple stimulus driving modes.In this paper, the major work is to design a hydrogel with more complex responsive shaping behavior and a device which exhibits controllable swimming motion. The results and conclusions are as follows:(1) The Clay(RDS)/poly(N-isopropylacrylamide) (PNIAAm) hydrogels (S-N hydrogels) and RDS/poly(N,N-dimethylacrylamide-co-2-methoxyethyl acrylate(DMAAm-co-MEA)) hydrogels(S-MD hydrogels) have been prepared by in-situ polymerization whose swelling behavior and deswelling behavior have been investigated. Both hydrogels’swelling behavior and deswelling behavior can be adjusted by changing their RDS and monomer content. Finally, S2N10 hydrogel and S2MD30 hydrogel are selected as the composite hydrogel matrix. By introducing magnetic nanoparticles (MNP) into the matrix gel and applying different magnetic field to construct different MNP spiral gradients, the RDS/P(DMAAm-co-MEA)/MNP (S-MD-MNP) composite hydrogel and the RDS/PNIAAm/MNP (S-N-MNP) composite hydrogel are prepared. It shows that the introduction of MNP don’t have a negative effect on the mechanical properties of the gel. The different MNP concentration gradients could be constructed by the magnetic field, which formed aggregates with different size between several tens of nanometers to several tens of microns. Besides, the concentration gradient of MNP in the gels has a great effect on the change of gels’shape during the response process, making the hydrogels achieve a more complex spiral deformation and display a pre-grammable responsive shaping behavior.(2) A series of copolymer gels which exhibit a melting-crystalling phase transition are synthesized by copolymerizing a-methacrylic acid with n-alkyl acrylate(n=14,16,18), whose density-via-temperature curve and DSC curve have been tested. These gels show an abrupt density change and an obvious hysteresis cycle during the whole melting-crystalling phase transition process. It also shows that the temperature of melting-crystalling phase transition increased with the increase of the side chain carbon number and the density increased with the increase in monomer content of MA. By comprehensive consideration, the poly(stearyl crylate -co- a-methacrylic acid) (P(SA-co-MA))hydrogels(S-M hydrogels) are selected as the matrix of the composite hydrogel. The S-M-G hydrogels are prepared by in-situ reducing the S-M-GO which was prepared by in-situ polymerization which reacted in 0.6wt% GO ethanol dispersion solution. The temperature-density curve, DSC curve and TEM indicated that GO has a good dispersity in S-M-G hydrogel and the gel has a well photothermal response property and realize a local melting-crystalling phase transition. Finally, the real-time controllable swimming motion of floating-diving, rolling, somersaulting, "bipedal-like" walking in water can be realized by designing or combining the shape and composited of S-M-G hydrogel and the location of NIR laser.(3) Two kinds of S-M hydrogels are prepared by solution polymerization and micelle polymerization. This work preliminarily aims to produce black Pt nanoparticles by in-situ in S-M gel network and design a device that can be drived by light and H2O2 solution. The temperature-density curve, DSC curve and the test of light-controlled motion show that S-M-SDS hydrogel can load Pt nanoparticles efficiently. The S-M-SDS-Pt hydrogel device has a good photothermal responsive property and catalytic capability, which is able to complete floating-diving motion in water and somersaulting movements on underwater and remote-controllable motion at 5wt%H2O2 solution surface.