Phytic Acid Layer Template-assisted Deposition Of TiO₂ Film Via Liquid Phase Deposition And Its Properties Research

Titanium dioxide （TiO₂） film has attracted a great deal of research interest because of its mertis such as high photocatalytic activity, stable physical and chemical properties, good mechanical performance, non-toxicity as well as good biocompatibility, etc. These mertis are projected to its potential application in a variety of areas such as photocatalysis, solar cells, optical devices, sensors, protective coatings and biomaterials, to name just a few. With the development of society, the TiO₂ film is desired to fulfill its diverse/versatile functionalities concomitantly in its realistic application. For instance, it needs to perform not only the required surface physiochemical properties but also the mechanical compliance on the rigid substrate, etc.To date, in the traditional preparation methods of TiO₂ film, such as chemical vapor deposition, pulsed laser deposition, sputtering deposition, electrodeposition, and so on, although these approaches can usually help to produce films with favorable suface properties, they are typically prone to the line-of-sight limit which may hardily render the films comply well with the substrates of irregular shapes, and they are usually expensive. A chemical way of liquid phase deposition （LPD） method was used to obtain crystalline TiO₂ films on aqueous solutions at low temperatures, and it is more advantageous such as simple operations, mild deposition conditions, unlimited substrate shape and low coat etc. However, the LPD has shortcomings. For instance, the TiO₂ films prepared by this method appear usually distinctly extraneous to the substrate without a transient interface, and therefore hardly adhere firmly unto the substrate, in other word, mechanical mismatch between the film and substrate is likely to elicit poor, unbalanced interplay between them. Only by improving the deposition parameters such as temperature and pH can not effectively solve the fundamental problem. Therefore, this paper designs a template layer as mediator to regulate the deposition of TiO₂.In present work, we employ phytic acid molecule with a number of phosphonic functional groups as a template layer to mediate TiO₂ deposition via LPD. Through the characterization methods of SEM, AFM, FT-IR, XPS, and XRD to analyze the material characteristics of the modified TiO₂ films, we finally found that PA layer template-assisted deposition of thin TiO₂ films were implemented successfully, and the films quality were also improved; PL spectra and Mott-schottky plot were used to dicussed the surface electrical properties of modified TiO₂ films, and then through the water contact angle test to evaluation the surface free energy state, it displays that super-hydrophilic phenomenon （water contact angle is less than 5°） and more stable surface electronic state on the TiO₂ films; Three-point bending experiments were qualitatively evaluated mechanics-related behavior, it finally found that PA induced deposition of TiO₂ thin films can withstand greater plastic deformation （the degree of bending is 180°）, which exhibited excellent bending properties; Through the blood test and osteoblast culture in vitro to discussed the biocompatibility of all samples, it found that modified TiO₂ film reflects good biocompatibility, which showed excellent blood compatibility （not easily activate platelet） and good bone compatibility （osteoblast adhesion and proliferation easily）; At last, a combination of its excellent performance in all aspects, and without changing the film formation mechanism and process, we scientifically and reasonably designed PA/TiO₂ intercalated hybrid coatings on pure magnesium, and through multiple alternating deposition PA and TiO₂ layer, we found better corrosion protective effect is not depended on the alternating times, meanwhile, we finally found the sample of PA/TiO₂（5L） has the best corrosion protective effect on magnesium from the transient electrochemical test and long-term immersion test, its efficiency can reach 97.80%. Overall, this template-assisted deposition of TiO₂ film via surface-immobilized organic layer on rigid substrate has more superior performances, which will bring more potential application values in many fields.