Optical properties of paraffin suspension containing TiO2 nanoparticles

In this work, the optical constants and properties of paraffin suspension containing TiO2 nanoparticles(PSN)were studied. The PSN was prepared by the two-step method, and the optical constants of the suspension were calculated by the particle swarm double-thickness method. The effects of the optical path, concentration and particle size on the transmittance and the optical constants of the samples were compared and analyzed. The results show that the influence of particle size and concentration of TiO2 on the transmittance is more outstanding with the increase of the optical path. The difference of transmittance between PSN with small particle sizes (5-10 nm) and one with big size (20 nm) is up to 4.51 % at the optical path of 20 mm. The transmittance of PSN concentration of 40 ppm decrease by 68.01 % on average compared with 2 ppm suspension under the optical path of 20 mm in 350-850 nm band. The trends of the absorption coefficient and the absorption index are very steady, meanwhile, the value of the refractive index throughout keeping the range from 1.0-1.5. It can be provided that the concentration is the main factor affecting the absorption index and absorption coefficient, and the particle size of TiO2 is the secondary factor.