Phase Behavior and Lubricity of Aqueous PEOPPO- PEO and PPO-PEO-PPO Triblock Copolymer Solutions

Authors

Reza Taheri, University of WollongongFollow
Buyung Kosasih, University of WollongongFollow
Hongtao Zhu, University of WollongongFollow
Anh Kiet Tieu, University of WollongongFollow

RIS ID

127998

Publication Details

Taheri, R., Kosasih, B., Zhu, H. & Tieu, A. K. (2017). Phase Behavior and Lubricity of Aqueous PEOPPO- PEO and PPO-PEO-PPO Triblock Copolymer Solutions. Tribology Transactions, 60 (3), 460-468.

Abstract

Aqueous triblock copolymer solutions are potential low-cost, eco-friendly lubricants. However, as a solution, their phase changes with copolymer concentration and solution temperature, raising the question, “Does the phase change affect the formation of adsorbed layer and the lubrication performance?” This article studies the copolymer solution phase behavior and lubricity in response to the copolymer structure, concentration, and solution temperature. Four different triblock copolymers, two normal PEO-PPO-PEO and two reverse PPO-PEO-PPO composed of PEO poly(ethylene oxide) and PPO poly(propylene oxide), have been investigated. From cloud point and surface tension measurements, phase change and micellization are shown to depend on copolymer type, number of hydrophilic PEO blocks, and temperature. Furthermore it is found that the phase and the presence of micelles lead to significant variation in adsorbed copolymer mass and lubricity. Based on the observed phase behaviors, the lubricity of copolymer solutions is discussed with regard to aggregation and adsorption on the solid–liquid interface.