SOLUTION PROPERTIES OF HYDROPHOBICALLY END-CAPPED LOW-MOLECULAR-WEIGHT POLYETHYLENE GLYCOLS

The solution behavior of a series of polyethylene glycols (EO 4-35) es terified at both ends with behenic acid, H3C(CH2)(20)COOH, was evaluat ed in comparison with their monoesters. Understandably the solubility patterns of these esters in water are clearly governed by their hydrop hilic/lipophilic balance values. The gel permeation chromatography and viscosity data strongly suggest that the disubstituted homologues are more compact than the monosubstituted counterparts both in aqueous an d organic media. The ability of the diesters to aggregate in aqueous m edium is established from surface tension measurements and pyrene fluo rescence probe methods. The molecular area calculation based on surfac e tension values indicates that, at the air-water interface, the area occupied by the monoesters and diesters are comparable.