Fukuoka Tokuma, Morita Tomotake, Saika Azusa, Habe Hiroshi
Research Institute for Sustainable Chemistry, National Institute of Advanced Industrial Science and Technology (AIST).
J Oleo Sci. 2018 Dec 1;67(12):1609-1616. doi: 10.5650/jos.ess18116. Epub 2018 Nov 15.
Surface properties of cast films of poly(lactic acid) (PLA) containing 1 wt% of several glycolipid-type biosurfactants (BSs) were investigated. The wettability of PLA films containing a homologue of mannosylerythritol lipids (MEL-B), lactone-form sophorolipid (LSL), or cellobiose lipid (CL) was drastically higher than that of untreated PLA and several synthetic surfactants-containing PLA. Surface wettability was also dependent on the hydrophilicity of the substrate used during solvent casting of the PLA films. The wetting behavior of the opposing sides of MEL-B-containing films prepared on glass substrates differed significantly; the contact angle on the side of the film that had been in contact with the glass surface was significantly lower than that obtained on the side of the film that had been in contact with air. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) analysis results showed that the MEL in MEL-B-containing thin PLA cast films was localized to a thin surface layer. These results suggest self-assembly of MEL-B and micro-phase separation between the PLA matrix and MEL-B domains. This resulted in the localization and orientation of MEL-B at the surface of the cast PLA film, which determined its specific wetting behavior.
研究了含有1 wt%几种糖脂型生物表面活性剂（BSs）的聚乳酸（PLA）流延膜的表面性质。含有甘露糖赤藓糖醇脂同系物（MEL-B）、内酯型槐糖脂（LSL）或纤维二糖脂（CL）的PLA膜的润湿性显著高于未处理的PLA和几种含合成表面活性剂的PLA。表面润湿性还取决于PLA膜溶剂浇铸过程中所用基材的亲水性。在玻璃基材上制备的含MEL-B的膜两面的润湿行为有显著差异；与玻璃表面接触的膜面的接触角明显低于与空气接触的膜面的接触角。飞行时间二次离子质谱（TOF-SIMS）分析结果表明，含MEL-B的PLA薄流延膜中的MEL定位于薄表面层。这些结果表明MEL-B的自组装以及PLA基体与MEL-B域之间的微相分离。这导致MEL-B在流延PLA膜表面的定位和取向，从而决定了其特定的润湿行为。
