Microwave absorption in oligomers of ethylene glycol

The dielectric properties of biologically and pharmaceutically important lo w-molecular weight ethylene glycols H(-OCH2CH2-)(n) -OH (n=1,2,4,6) were in vestigated to clarify the effect of chain length on the dielectric properti es. The measurement of dielectric constant and dielectric loss was carried out over the frequency range 200 MHz to 20 GHz at temperatures of 25 degree s C to 55 degrees C. It is found that in these molecules microwave dielectr ic losses are significant. The dispersion behaviour of these molecules can be represented by Cole-Cole equation. The dielectric properties of these ho mologous ethylene glycols are discussed in terms of the effects of chain le ngth and intermolecular hydrogen bonds regarding the molecular conformation s. These wide frequency range dielectric data have also been discussed in v iew of the suitable selection of the oligomer of ethylene glycol for cosmet ic preparations and other pharmaceutical applications with the intention of protection of the skin from weak microwave radiations present in the surro unding environment. These systematic microwave dielectric data with frequen cy and temperature variation are not available and are provided in this pap er.