Quantization of the solvent effect on the adsorption of poly-γ-benzyl- l-glutamate

• Published in: Journal of colloid and interface science 1978-01, Vol.67 (1), p.118-126
• Main Authors: Balik, C.Maurice, Hopfinger, A.J
• Format: Article
• Language: English
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/0021-9797(78)90219-9

The isothermal adsorption of poly-γ-benzyl- l-glutamate (PBLG) onto alkali-halide (100) surfaces has been studied, with special consideration given to the role of solvent. The solvent effect was empirically quantized using a two-dimensional (polar/nonpolar) solubility parameter. The nonpolar component ( δ d) has been correlated with PBLG solubility. The polar component ( δ a) was correlated with the state of aggregation of PBLG in solution, as well as with the adsorption behavior of PBLG onto alkali-halides. PBLG having a molecular weight ≅300,000 was found to be soluble in solvents and solvent mixtures having δ d in the range of 8.0–9.3 (cal/cm 3) 1 2 and simultaneously having δ a in the range of 1.0–8.7 (cal/cm 3) 1 2 . Pure solvents with low δ a values (e.g., δ a ≅ 1.0) allow the formation of liquid crystalline phases of PBLG, while PBLG is completely unaggregated in solvents with δ a ≥ 5.2. The amount of adsorption of PBLG onto alkalihalides decreases with increasing δ a of the solvent.