Superhydrophobic Porous PLLA Sponges with Hierarchical Micro‐/Nano‐Structures for High‐Efficiency Self‐Cleaning. Issue 22 (23rd October 2019) - Wang, Yongtao
Abstract: Porous poly (l ‐lactic acid) (PLLA) sponges have received rapid development in the materials science and energy fields due to their good biocompatibility and degradability. Herein, hierarchical micro‐/nano‐structures of PLLA sponges are successfully prepared by the microphase separation method to investigate the influence of non‐solvents on PLLA microtopography. The interaction ability between PLLA and various alcohol non‐solvents is precisely calculated by using the Flory–Huggins equation. SEM results show that the porosity of PLLA surfaces increases with increasing non‐solvent solubility parameters at a certain range. When the solubility parameters of alcohol non‐solvents are much higher than that of PLLA, PLLA bulks accumulate on the surfaces, mainly caused by its insolubility. DSC curves disclose that the crystallinity has a positive relationship with contents and solubility parameters of alcohol non‐solvents. Furthermore, these porous PLLA surfaces show strong water repellency and self‐cleaning ability so that the contaminant can be quickly cleared away from the PLLA surfaces. This study provides a new insight into understanding the formation process of PLLA porous materials and the wetting variation for high‐efficiency self‐cleaning. Abstract : Hierarchical micro‐/nano‐structures are successfully prepared by a microphase separation method to investigate the influence of various alcohols on PLLA micro‐topography by precisely adjusting the Flory–Huggins interaction parameter. The roughness of porous PLLA surfaces improves high contact angle but lowers the sliding angle, and even shows strong pollution‐resistant abilities.