Salt Induced Micellization of Ethylene Oxide-Propylene Oxide Block Copolymers in Aqueous Solution


Affiliations

  • South Gujarat University, Department of Chemistry, Surat, 395 007, India

Abstract

Micellization of three ethylene oxide-propylene oxide block copolymers L43 (EO6PO21EO6, mw PPO = 1220, %PEO = 30), PI23 (EO20PO69EO20, mw PPO = 4025, %PEO = 30) and F127 (EO99PO69EO99, mw PPO = 4025, %PEO = 70) in aqueous sodium chloride solution was examined by surface tension, dynamic light scattering and viscosity measurements over the temperature range 30-50°C. Salt induced micellization and micelle growth was observed; the presence of added sodium chloride develops hydrophobicity in the PPO moiety and reduces hydrophilicity of PEO moieties favouring micellization of these block copolymers at relatively lower concentrations than in water at ambient temperature. The results are discussed in terms of CMC, area/molecule, and hydrodynamic size of micelles. Aggregation pattern of copolymers with different molecular characteristics showed similarity but with some marked differences.

Keywords

Block Copolymers, Micellization, Hydrophobicity, Aggregation, Hydrodynamic Radius.

Subject Discipline

Chemistry

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