Gg. Pimenov et al., MOBILITY OF MOLECULES OF A LIQUID WITHIN PORES OF AEROSIL, Colloid journal of the Russian Academy of Sciences, 57(1), 1995, pp. 113-115
The self-diffusion coefficients D and times of longitudinal (T-1) and
transverse (Ttl magnetic relaxation of protons in polar (dimethyl sulf
oxide, dimethyl phthalate) and apolar (tridecane) liquids incorporated
into aerosil pores have been measured using the NMR method. The times
measured for polar molecules (Ttl diminishes by two orders of magnitu
de or greater, compared with apolar liquids. Variations in the self-di
ffusion coefficients of the liquids are virtually independent of their
polarity. The results obtained are attributed to the orienting influe
nce of the surface of aerosil particles on the polar molecules, result
ing in anisotropy of their rotational mobility. The parameters of anis
otropy and times of isotropic reorientation were estimated as 1.6 x 10
(-7) and 6.8 x 10(-7) s for molecules of dimethyl sulfoxide and dimeth
yl phthalate, respectively.