Fabrication Of Hydrophobic Coatings On Betula Alnoides Wood With Different Alkyltrichlorosilanes

To study the hydrophobic properties of Betula alnoides wood modified by alkyltrichlorosilanes, four alkyltrichlorosilanes with different chain lengths were used to prepare hydrolytic solutions by adding 0.25% (v/v) of alkyltrichlorosilane to anhydrous toluene, and the wood samples were immersed in the hydrolytic solutions for 4 h. The surface chemical compositions of the samples were analyzed by X-ray photoelectron spectroscopy (XPS) and Varian 640-IR Fourier Infrared Spectrometer (ATR-FTIR), the surface morphology of the samples was observed by scanning electron microscopy (SEM), and the wettability of the modified wood was investigated using an optical contact angle goniometer. The results demonstrated that treatment with alkyltrichlorosilanes introduced Si and low surface energies of –CH2 and –CH3 on the surface of Betula alnoides wood. The –CH2 and –CH3 content increased with the increase in chain length. Alkyltrichlorosilanes formed a different micro or nanoscale roughness on the surfaces of the wood samples. The water contact angles of all coatings of alkyltrichlorosilanes are greater than 131.3±2.4∘, and greater than 115.5±0.9∘ after 180 s. The water absorption decreases with the increase in chain length. The water absorption of the uncoated sample is 44.0±1.9 wt.%, while those of samples modified by MTCS and OTCS are 18.0±0.9 wt.% and 11.0±0.0 wt.%, respectively.