Preparation Of Composite Acrylic Hydrogel And Its Electrical Response

In order to prepare hydrogels with excellent response for electric field, our team chose acrylic acid containing a carboxyl group as the basic raw material. According to the electric response theory, we add chitosan, Fe3+or Al3+respectively to obtain an interpenetrating network structure hydrogel and metal ion assisted crosslinking acrylic acid hydrogel to improve the response performance for electric field of acrylic acid hydrogel in this thesis. This paper explored the impact about component concentration and the applied DC (direct-current) electric field intensity on acrylic hydrogel electric field response performance. Storage modulus about hydrogel was tested by dynamic viscoelastic spectrometer DMAQ800 test. In addition, the difference about the storage modulus between the hydrogels gelled in presence or absence of an electric field was tested to study the electrical properties of the hydrogel response. Specific electric field response performance about three hydrogels was presented as follows:1. N, N- methylene-bis-acrylamide as crosslinking agent, a certain percentage of chitosan was dissolved in a concentration of acrylic acid to obtain a solution. After a while reacting with a certain amount of potassium persulfate, the pH was adjusted, and a certain amount of N, N-asia methylene-bis-acrylamide was added to obtain a homogeneous mixture. Then, the mixture was poured into a uniform mixed system powered plexiglass box and placed under the heating conditions in the presence and absence of electric field to happen fast crosslink. In this stage can we obtained two different chitosan/acrylic hydrogel with interpenetrating network structure:A-hydrogel (E≠0 kV/mm) and B-hydrogel (E= 0 kV/mm). For hydrogel with different substrate concentrations under the same electric field, its storage modulus increase with the increasing substrate concentration, and the mechanical strength of A and B- hydrogel are changing. In addition, for A- hydrogel, the applied electric field strength was from 0.6 to 1.2 kV/mm. We found that the storage modulus of the A- hydrogel is always larger than B- hydrogel’s, and storage modulus increase with the growth of the applied electric field intensity. This indicates that the chitosan/acrylic acid interpenetrating network structure hydrogels have positive response to external direct-current electric field. Along with the increase of applied electric field, the response is reinforced. The microstructure of the hydrogels was observed by environmental scanning electron microscope. We found that the microstructure of A-hydrogel which is under the electric field is more order than B-hydrogel which is no impact of the applied electric field. Orderly microstructure of hydrogel was caused by the applied electric field.2. In the similar way, N, N- methylene-bis-acrylamide as crosslinking agent, a certain percentage of acrylic acid was taken to mixture with amount of potassium persulfate. After a while, Fe3+ and N, N-Asia methylene-bis-acrylamide was added to the solution, then the mixture was poured into a uniform mixed system powered plexiglass box and placed under heating conditions in the presence or absence of electric field to fast crosslink. Here, two kind of hydrogels were obtained—A-hydrogel (E≠0kV/mm) and B-hydrogel (E=0 kV/mm). By comparing the storage modulus of A-hydrogel and B- hydrogels under different concentrations of to study the hydrogel’s the electric field response performance. The results showed that Fe3+ assistant crosslinked acrylic hydrogel has a positive response to the electric field, the response increased with the increase of the applied electric field, In addition, this response varies component concentration changing.3. In the similar way with the 2, we prepared Al3+ assistant cross-linked acrylic acid hydrogel. Its electric field response performance was also studied with the changes about the concentration and external direct-current electric field. The experiment results showed that Al3+ assistant cross-linked with acrylic acid hydrogel has a positive response to the applied electric field, which was similar to Fe3+ assistant cross-linked with acrylic acid hydrogel. In addition, the response increases with the enhancement of the electric field. Responsiveness with different component concentrations was also different. However, comparied with Fe3+ assistant cross-linked acrylic acid hydrogel, Al3+ cross-linked acrylic acid assisted hydrogel has higher response which is that the response to the electric field is stronger with changes of the electric field.