Superhydrophobic, Self-Cleaning, and Robust Properties of Oriented Polylactide Imparted by Surface Structuring
Yuan Chen, Xinrui Gao, Hua‐Dong Huang, Ling Xu, Xu Ji, Gan‐Ji Zhong, Hao Lin, Zhong‐Ming Li
Abstract
Polylactide (PLA), which features desirable biodegradability and easy melt processability, has been recognized as one of the most promising environment-friendly polymer materials. However, its poor hydrophobicity and toughness limit its application in moisture-proof, barrier, and self-cleaning fields. In this work, we report a facile and efficient method capable of mass fabrication of PLA films with excellent comprehensive properties including superhydrophobicity, good stiffness-toughness balance, and self-cleaning function. Through a casting-thermal stretching process, PLA films with an oriented structure turn from inherently brittle to robust. By employing the breath figure method to assemble a relatively ordered microporous structure and treating the surface with hydrophobic silica nanoparticles, a micro-/nanostructured surface with low surface energy is constructed, which leads to superhydrophobicity. Meanwhile, a highly oriented structure provides excellent mechanical properties with a tensile strength of 92.2 MPa and an elongation at break of 112.3%, even after surface modification. The PLA film exhibits a good self-cleaning property and heat, acid, and water resistance, owing to the high crystallinity and stability of silica particles. This work could provide a facile approach with industrial potential to fabricate PLA materials with special wettability and excellent mechanical properties for self-cleaning and moisture-proof packaging applications.