Sol-gel Titania Based Antimicrobial Film And Its Properties

With the progress of our society and the advancement of living standard,people are paying more and more attention to the healthy environment where they live.Much research has been done on the photocatalytic properties of TiO2 since the metaphase of 1970s. Taking advantage of TiO2 to remove and degrade pollutants has become a very active research direction in the field of environment science. However the application of photocatalysis studies still uses slurries of TiO2 particles which are difficult to be recovered. The immobility of semiconductor thin films is one of the effective methods to solve this problem,while sol-gel technology can realize the immobility of thin films. Scientists have found out that TiO2 has broad-spectrum resistance and can suppress or kill common pathogen to some extent by illumination with light. Ag+ ,Cu2+ are capable of killing most common bacteria,especially Ag+has strong effect in killing bacteria and its effect can last for long.The consumption of Ag+ is very small for it to kill bacteria. Ag+ is bioclean and isn't irritant.Taking TiO2 thin films as the carrier of Ag+ ,Cu2+ et al,as can complement the antibacterial properties and the antibacterial properties can be enhanced greatly.Under such situation ,in this article,we reviewed the development ,preparation method and antibacterial properties of antibacterial agents.The preparation method,photocatalytic activities and antibacterial of nanometric TiO2 thin films were also discussed in detail.Preparation process of nanosized TiO2 membrane was studied,and the fixation of TiO2 was solved and firm transparent anatase TiO2/glass thin films with nano-crystalline have been prepared by the sol-gel processing using tetrabutyl titanate as a precursor in this paper.Hydrolysis and condensation velocity could be controlled and sol with good filming property was prepared by changing the matching of water,catalyzer,precursor and solvent etc in solution.Good matching ratio was gotten after lots of experiments and analysis.nC2H5OH/nTi(OC4H9)4=45(mol ratio),nH2O/nTi(OC4H9)4=2(molratio),nHNO3/nTi(OC4H9)4=0.3(molratio),n(CH3CO)2 CH2/nTi(OC4H9)4=0.5(molratio). Optimal hydrolysis temperature is 30 C, optimal annealing temperature is 450 C,optimal annealing time is 1 hour.Transparent inorganicantibacterial film can be formed on glass plate under the dropping rate 10cm/min,heat treated at 450"C. Ag+-doped thin films, Cu2+-doped thin films,thin films doped with Ag+ and Cu2 are prepared by adjusting the content of Ag+, Cu2+ in the sol.Ion-doped TiO2 thin films were also studied in this paper.The influence of doping ratio on the photocatalytic properties was studied. Ag+/Ti=5%(molratio) and Cu2+/Ti=2%(molratio) have the optimal photocatalytic effect on TiO2 separately.The samples were tested by XRD,SEM methods. And their photocatalytic performance has been tested in terms of film thickness, time duration, annealing temperature,the ratio of dopant.Then the antibacterial capability of the prepared TiO2 thin films was evaluated.According to the experiments to Escherichia coli,metal ions such as Ag+ or Cu2+ can be antibacterial by contact. TiO2 thin film is antibacterial through photocatalysis. And if Ag+ or Cu2+ was doped with TiO2 .cooperation effects which can enhance the antibacterial effect happen. And if Ag+and Cu2+ are doped with TiO2 at the same time,more antibacterial effect can be enhanced.Studies about this field was seldom published in the past.