Preparation and Interfacial Properties of a Novel Biodegradable Polymer Surfactant: Poly(ethylene oxide monooleate-block-DL-lactide)

• Published in: Macromolecular bioscience 2005-11, Vol.5 (11), p.1066-1073
• Main Authors: Nishino, Satoru, Kitamura, Yoshiro, Kishida, Akio, Yoshizawa, Hidekazu
• Format: Article
• Language: English
• Subjects: Applied sciences; biodegradable; Biodegradation, Environmental; contact angle; Exact sciences and technology; interfacial tension; Organic polymers; Physicochemistry of polymers; Polyesters - chemical synthesis; Polyesters - chemistry; Polyethylene Glycols - chemical synthesis; Polyethylene Glycols - chemistry; Polymers - chemical synthesis; Polymers - chemistry; Polymers with particular properties; Preparation, kinetics, thermodynamics, mechanism and catalysts; surface free energy; Surface-Active Agents - chemical synthesis; Surface-Active Agents - chemistry; surfactants
• ISSN: 1616-5187; 1616-5195
• DOI: 10.1002/mabi.200500124

In this paper, we report a novel synthesis of poly(ethylene oxide monooleate‐block‐DL‐lactide) (MOPEO‐PLA) in the presence of stannous 2‐ethylhexanoate catalyst. By utilizing the surfactant property and the reactive double bond of the amphiphilic MOPEO‐PLA, various characteristics of PLA microspheres, such as surface and internal structure, surface morphology, release property, and so on, may potentially be controlled. MOPEO‐PLA was found to be hydrophobic enough to prevent loss by dissolution into aqueous solution, which is often a problem for MOPEO. Furthermore, the interfacial tension measurements of a MOPEO‐PLA/toluene/water system revealed that MOPEO‐PLA had a good surface activity almost equal to that of MOPEO. The MOPEO‐PLA/PLA blend films were prepared by solvent casting on a water layer. Contact‐angle measurements of MOPEO‐PLA/PLA blend films confirmed that the hydrophilic PEO segments were selectivity accumulated at the oil/water interface. Moreover, the surface free energy on the ‘water side’ of the MOPEO‐PLA/PLA blend films was increased because of the increase in polar components as a result of the ether bonds of the PEO segments. Schematic illustration of the adsorption property of a) MOPEO‐PLA with a high‐molecular‐weight PLA segment and b) MOPEO‐PLA with a low‐molecular‐weight PLA segment at an ethyl acetate/water interface.