Stable superhydrophobic wood surface constracting by KH580 and nano-Al2O3 on polydopamine coating with two process methods

Abstract

Superhydrophobic treatment of wood is of great significance for improving the service life of wood and expanding its application fields. In this study, two process methods were designed to meet above requirements. Using polydopamine (PDA), 3-mercaptopropyltriethoxysilane (KH580) and nano-Al2O3 as the micro-nano structure maker and octadecyltrichlorosilane (OTS) as a low surface free energy agent to modify rough surface in order to prepare superhydrophobic wood samples (Wood@One-step and Wood@Two-step). The contact angle (CA) and sliding angle (SA) of the Wood@One-step were 155.3° and 4.76°, respectively; the CA and SA of the Wood@Two-step were 152.9° and 7.65°, respectively. Surface electron microscopy (SEM) images showed that the surface of Wood@One-step and Wood@Two-step were honeycomb structure and layered stacking structure respectively. The superhydrophobic properties of Wood@One-step were superior because of its more reasonable micro-nano roughness. Atomic force microscope (AFM) images presented that the nano-Al2O3 particles could effectively provide nano-level roughness. X-ray photoelectron spectroscopy (XPS) analysis showed that KH580 had covalent interaction with PDA. Thermogravimetric (TG) analysis, the immersion of acid-base solution and organic solution revealed that obtained superhydrophobic wood samples had excellent stability in the face of environmental challenges.