Liquefied-Wood-Based Polyurethane–Nanosilica Hybrid Coatings and Hydrophobization by Self-Assembled Monolayers of Orthotrichlorosilane (OTS)

Abstract

We have produced hybrid liquefied-wood-based polyurethane (LW-PU) and LW-PU/nanosilica hybrid coatings for wood substrates. The prepared hybrid polyurethane coatings were hydrophobized by self-assembled monolayers of orthotrichlorosilane (OTS) via a sol–gel dipping process. The nanosilica addition into the LW-PU system enhanced the physical properties of coatings like surface hardness and stability toward cold liquids. The OTS hydrophobized coatings were characterized by Fourier transforms infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and thermogravimetric analysis (TGA). The surface became hydrophobic as the contact angle (CA) for the water droplet on a modified hybrid coating was ∼115° and very stable. The FTIR, SEM, and EDS analysis confirmed the formation of OTS monolayers on hybrid coatings.