In this study, a colloidal suspension, composed of polymethylsilsesquioxane (PMS) and Cu-containing nanoparticles (CuNP), was prepared through simple neutralization reaction using sodium methyl siliconate (SMS) and CuCl₂solutions. The nano-structure of CuNP was investigated by TEM and the results showed that lamellar crystal Cu(OH)₂with size of around 10 nm was imbedded in PMS nano-particle. The FTIR also confirmed the presence of small amount of PMS in CuNP. The specific nano-structure of CuNP resulted in excellent thermal stability based on TG analysis. After dip-coating in optimized conditions and drying, a PMS/CuNP xerogel coating layer was generated at the bamboo surface, endowing superhydrophobic and excellent anti-mildew performance according to ASTM D3273-16. The water contact angle (WCA) reached up to 151.3 ± 1.9° and the mildew resistance grade was marked as 10 where no mold was found at the surface after 4 weeks incubation.

Poplar (Populus tomentosa Carr.) solid wood was surface densified in the tangential direction, and the vertical density profile (VDP) and hardness of the treated and untreated samples were measured. The effects of the process parameters on the VDP and hardness were investigated. To explicitly describe the VDP of the surface densified wood, five indices (AD, ADx, PD, PDi, and DTh) were used. The compressing temperature and closing speed influenced the formation and shape of the VDP. A higher temperature yielded a greater PD and Pdi, and a faster closing speed yielded a higher PD, but smaller PDi and DTh. Increasing the compression ratio increased the AD, ADx, and maximum load, and the poplar wood was compressed in the overall thickness as the compression ratio exceeded a certain degree. The Janka hardness of the poplar wood was significantly improved after surface densification; a higher temperature resulting in a higher surface hardness was explained by the higher PD. The closing speed and compression ratio affected the hardness by impacting the VDP, specifically the PD and DTh indices. When the PD and DTh were greater the surface hardness was greater. By this study, a compressing temperature of 140 to 160 °C and the closing speed of 10 mm/min is recommended, and to prevent the deformation of unheated side of the wood samples and obtain a higher surface hardness, the compression ratio is restricted to 20%.