Dynamics of alcohols dispersed with aerosils

We investigated the dynamics of three alcohols dispersed with aerosils in the frequency range from 1 MHz to 1 GHz with dielectric relaxation spectroscopy. In comparison with the pure systems, no new relaxation processes were observed in this frequency range. The main relaxation time in octanol decreased with increasing aerosil concentration. In ethanol and glycerol there was no significant change in the relaxation times found. These results are different from those well-known for liquid crystal–aerosil dispersions. We think that the absence of the retarded relaxation at the surface of the aerosils can be explained by the fact that the character of the hydrogen bond is not too much different for an intermolecular one as compared to an alcohol–aerosil bond. Also it seems that the (shorter) alcohols are already disordered to an extent that the addition of an extra disordering agent does not change the dynamics.