Preparation And Properties Of Carbon Quantum Dot-biquaternary Ammonium Salt Compositefluorescent Hydrogel

Antimicrobial is always an important issue in the field of biomedical materials.As a new type of antibacterial material,antibacterial hydrogel is often used as a wound dressing in medicine.It can block the contact between bacteria and wounds,and inhibit the growth and reproduction of microorganisms in a humid environment.Among them,the quaternary ammonium salt gel has attracted the attention of researchers because of its advantages of easy availability and environmental friendliness.The biocompatible carbon quantum dots are doped into the quaternary ammonium salt gel.The unique optical properties of the carbon quantum dots make the quaternary ammonium salt gel visible while having antibacterial properties,showing more application prospect.This experiment is aimed at preparing antibacterial hydrogels with fluorescent properties,which are generally divided into the preparation of carbon quantum dots and the preparation of carbon quantum dot composite hydrogels.The first part uses o-phenylenediamine and urea as precursors to prepare carbon quantum dots with yellow fluorescence by hydrothermal synthesis.The synthesis process of carbon quantum dots is optimized.When the mass ratio of the two raw materials is 1:5,the reaction temperature is 160 oC,the reaction time is 5 hours,and the concentration is 5mg/mL,the fluorescence intensity of the obtained carbon quantum dots is the strongest..The performance and structure of carbon quantum dots were characterized by infrared,ultraviolet,fluorescence,transmission electron microscopy,and X-ray diffraction.The results showed that carbon quantum dots were spherical particles with a uniform particle size distribution and an average particle size of 4.3nm.Lattice fringes with a fringe pitch of 0.192nm.The surface is rich in oxygen-containing functional groups such as hydroxyl groups and carbonyl groups.It is irradiated with light at 390 nm and emits yellow fluorescence in the 567 nm band,and the fluorescence is stable.The second part first uses 2-(Dimethylamino)ethyl methacrylate(DMAEMA)and 3-chloro-2-hydroxypropyltrimethylammonium chloride(3-Chloro-2-hydroxypropyltrimethylammonium chloride(CHPTAC)to undergo a nucleophilic substitution reaction to prepare a new type of double quaternary ammonium salt monomer with double bonds.Its structure was proved by infrared spectroscopy and nuclear magnetic hydrogen spectroscopy,and its synthesis process was optimized.DMAEMA When the molar ratio to CHPTAC is 1.5:1,the reaction temperature is 70 oC,and the reaction time is 12h,the yield of quaternary ammonium salt monomer is 64.6%.The solution quaternary ammonium salt-acrylic acid copolymer is prepared by solution free radical copolymerization,and the yellow fluorescent carbon quantum dots are physically doped into the quaternary ammonium salt gel by soaking to obtain a fluorescent quaternary ammonium salt gel.The infrared spectroscopy,fluorescence spectroscopy,mechanical properties,antibacterial properties were characterized and tested.The results show that the carbon quantum dots are successfully doped and the hydrogel has fluorescent properties,and the mechanical properties are also enhanced.Compared with pure acrylic resin,it has a significant bacteriostatic effect.