Synthesis And Application Of Hydrogels Based On Electrochemical Response

Stimuli-responsive self-assembling systems have attracted much interest from researchers because of their potentials in a broad range of fields, such as drug delivery systems, sensor systems, and functional nanodevices, photochemical, temperature, chemical (pH, redox), and electrical stimuli are all reasonable possibilities to exert control on host-guest systems.One of the largest usages for polyacrylamide is to flocculate solids in a liquid. This process can be applied to water treatment, and processes like paper making, screen printing. Another common usage of polyacrylamide and its derivatives is in subsurface applications such as enhanced oil recovery. High viscosity aqueous solutions can be generated with low concentrations of polyacrylamide polymers, and these can be injected to improve the economics of conventional water flooding. In view of polyacrylamide interesting rheological properties, this system could potentially be used as oil fracturing. Thickening and gel breaking is one of the important properties of fracturing fluids. Most of the fracturing fluid had good thickening properties, but gel breaking properties is unsatisfactory.Polyacrylic acid is a class of fascinating soft and wet materials consisting of a three-dimensional crosslinked macromolecular network and a swelling medium, water. Because of the high water content and conceptual similarity to living soft tissue in numerous features, hydrogels offer promising opportunities for development of implantable scaffolds in tissue engineering and regenerative medicine. However, conventional hydrogels are unsuitable for the replacement of load-bearing tissues due to their intrinsic low mechanical properties caused by high dilution of polymer chains in the swollen state as well as the heterogeneity of the network formed. There used to be a common belief that the poor mechanical strength of hydrogels is insurmountable. A high strength hydrogel was fabricated by one-step copolymerization of dipole-dipole interaction containing monomer, acrylonitrile. The hydrogels became toughened and ductile. Due to there is a lot of -COOH on PAA chain, which can covalent pectinase.1. We designed voltage-responsive molecular hydrogel of PAM-Fc and PEG-β-CD to give electrochemical control to the hydrogel systems. Once in the earth, the mixture undergoes electrical stimuli triggered gelation, forming a hydrogel that is able to thickening and gel breaking in a controlled fashion. When the concentration was enough, PAM-Fc subsequently self-aggregated into a 3D network, i.e. hydrogel formation. We can realize the reversible assembly-disassembly of this sol-gel system by applying a repeatedly alternating positive-negative voltage. The reversible voltage-responsive ability of this system makes it a potential material for fracturing fluids. A primary experiment of controlled thickening and gel breaking based on this system was conducted successfully. In view of its interesting rheological properties, this system could potentially be used as oil fracturing. Once in the earth, the mixture undergoes electrical stimuli triggered gelation, forming a hydrogel that is able to thickening and gel breaking in a controlled fashion.2. We designed voltage-responsive molecular hydrogel of PAA-PAN-Fc and PAA-PAN-CD to give electrochemical control to the hydrogel systems. The characterization of these two polymers by FT-IR absorption spectra,1H NMR and GPC confirmed their structures and molecular weight. The CV was utilized to characterize the interactions between the host and guest polymers. DLS and TEM were used to characterize the size, size distribution and appearance of the molecular hydrogel. Finally, through electrochemical control, the reversible assembly-disassembly transition of the molecular hydrogel was realized and induce the gel-sol transition. The supramolecules self-aggregated into a 3D network in response to electrochemical control, forming an electrical stimuli reversible "smart" hydrogel. Due to there is a lot of-COOH on PAA chain, which can covalent pectinase. A high strength hydrogel was fabricated by one-step copolymerization of dipole-dipole interaction containing monomer, acrylonitrile. The hydrogels became toughened and ductile. Due to there is a lot of-COOH on PAA chain, which can covalent pectinase. The hydrogels became toughened and ductile.