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Tuning photo-catalytic activities of TiO2 nanoparticles using dimethacrylate resins



Jirun Sun, Stephanie S. Watson, David Allsopp, Deborah Jacobs, Drago Skrtic


Unique photo-catalytic activities (PCAs) of titanium dioxide nanoparticles (TiO2 NPs) made them attractive in many potential applications for medical devices. This study examined the benefits of the PCAs of TiO2 NPs through functionalization of the TiO2 NPs and/or varying chemical structures of dimethacrylate resins. TiO2 NPs were functionalized to improve the PCAs and bonding to the resin network. The PCAs of TiO2 NPs were evaluated using electron paramagnetic resonance (EPR) and UV-vis spectroscopy to determine the amount of radicals generated and the energy required for their production, respectively. The beneficial effects of the radicals were assessed through the improvement of degree of vinyl conversion (DC; quantified by infrared spectroscopy); and modification of resin hydrophilicity (expressed by measuring the water contact angle (WCA)). One- way ANOVA was used to indicate significant differences between the experimental groups. Light-cure resins were formulated from ethoxylated-bisphenol-A-dimethacrylate (EBPDMA), 2-bis(4-(2-hydroxy-3- methacryloxypropoxy)phenyl)propane), triethyleneglycol dimethacrylate, pyromellitic-glycerol- dimethacrylate and/or hydroxyethyl-methacrylate monomers. In addition, the viscosity and number of hydroxyl groups/carboxylic acid groups of the experimental resins were correlated with the PCAs of TiO2 NPs. Results clearly showed that the functionalized TiO2 NPs enhanced PCAs in terms of generating radicals under visible light irradiation. Hydroxyl and carboxylic acid functionality played an important role in DC enhancement and hydrophilicity modification. For the EBPDMA resin, the increase in DC was up to 22 % by adding only 0.1 wt% TiO2 NPs. Viscosity of the resins had minimal role in DC improvement. In resins with abundant hydroxyl groups, radicals were more effective in making the resin more hydrophilic. Dramatic improvement in DC and a significant change in resin hydrophilicity can be achieved through modifying resin composition.
Dental Materials


photoreactivity, titanium dioxide, free radical, dimethylacrylate resins


Sun, J. , Watson, S. , Allsopp, D. , Jacobs, D. and Skrtic, D. (2015), Tuning photo-catalytic activities of TiO2 nanoparticles using dimethacrylate resins, Dental Materials, [online], (Accessed May 23, 2024)


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Created August 19, 2015, Updated October 12, 2021