Surface charge properties of titanium dioxide in water and propylene g lycol have been discussed by proton-transfer phenomena.Electrophoresis shows s ignificant differences between each type of titanium dioxide partic...Surface charge properties of titanium dioxide in water and propylene g lycol have been discussed by proton-transfer phenomena.Electrophoresis shows s ignificant differences between each type of titanium dioxide particles and betwe en the two dispersion media.In aqueous solvent,the sign of the charge for tita nium dioxide would change due to pH and surface chemical composition.However,i n propylene glycol pH value could not result in the sign of the charge for uncoa ted titanium dioxide.Furthermore,the effects of both alumina and silica coatin gs and media on the surface charge properties of titanium dioxide are due to pro ton-transfers.The acidity of hydroxyl groups on oxides surface is believed to be the direct reason that make them have different charge properties in solvents .It is favorable for the hydroxyl groups on the surface of particles to donate protons,as was observed by negative charge pertaining for dispersion in water a t most values of pH.While in propylene glycol titanium dioxide particles are fo rced to accept protons,resulting in positively charged particles.Small amounts of water have a significant effect on the sign of the charge for uncoated titan ium dioxide.展开更多
文摘Surface charge properties of titanium dioxide in water and propylene g lycol have been discussed by proton-transfer phenomena.Electrophoresis shows s ignificant differences between each type of titanium dioxide particles and betwe en the two dispersion media.In aqueous solvent,the sign of the charge for tita nium dioxide would change due to pH and surface chemical composition.However,i n propylene glycol pH value could not result in the sign of the charge for uncoa ted titanium dioxide.Furthermore,the effects of both alumina and silica coatin gs and media on the surface charge properties of titanium dioxide are due to pro ton-transfers.The acidity of hydroxyl groups on oxides surface is believed to be the direct reason that make them have different charge properties in solvents .It is favorable for the hydroxyl groups on the surface of particles to donate protons,as was observed by negative charge pertaining for dispersion in water a t most values of pH.While in propylene glycol titanium dioxide particles are fo rced to accept protons,resulting in positively charged particles.Small amounts of water have a significant effect on the sign of the charge for uncoated titan ium dioxide.
