MOBILITY OF MOLECULES OF A LIQUID WITHIN PORES OF AEROSIL

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.