Construction of CNC@SiO2@PL Based Superhydrophobic Wood with Excellent Abrasion Resistance Based on Nanoindentation Analysis and Good UV Resistance

Abstract

Construction of superhydrophobic woods with high abrasion resistance is still a major challenge, and micro analysis for abrasion resistance is scarce. To improve these issues, cellulose nanocrystals (CNC)@SiO2@phosphorylated lignin (PL) rods were prepared by SiO2 in situ generated on CNC, and then the modified lignin attached to the CNC@SiO2 rods surface. Subsequently, the superhydrophobic coating was constructed using hydrophobic modified CNC@SiO2@PL rods as the main structural substance by simple spraying or rolling them onto wood surfaces, and both polydimethylsiloxane (PDMS) and epoxy resin were used as the adhesives. The resulting coating had excellent superhydrophobic properties with a water contact angle (WCA) of 157.4° and a slide angle (SA) of 6°. The introduced PL could enhance ultraviolet (UV) resistance of the coating due to the presence of these groups that absorbed UV light in lignin. In the abrasion resistance test, compared with the SiO2/PL coating, the abrasion resistance of the one with CNC was much higher, suggesting that CNC could improve the abrasion resistance of the coating due to its high crystallinity and excellent mechanical strength. The coating with PDMS performed better than the one with epoxy resin because the soft surface could offset part of the external impact by deformation in the abrasion process. This was also consistent with the results of the nanoindentation (NI) tests. In view of the simple preparation and good performance, this superhydrophobic wood will have broad application potential.

Superhydrophobic Wood Surfaces: Recent Developments and Future Perspectives

“…In this section, these methods of preparing SHWSs have been summarized in Table 1, and then they will be separately introduced and summarized in details as well as their own advantages. Pine lumber Cu FAS Immersed in NaOH at 70 • C for 10 min 160 [48] Balsa wood rGO PDMS Immersed in GO solution, then reduced to rGO@wood 152 [49] Ash wood -APTES Immersed at 60 Birch wood SiO 2 PDMS 0.3 MPa at a distance of 10 cm 170 [60] Balsa wood Soot PDMS Sprayed for 3 s 160 [61] European beech wood AKD wax Oven-dried at 45 • C for 10 min 160 [62] Beech wood CNC@SiO 2 @PL rod PDMS Dried at 150 • C for 2 h 157.4 [63] Wood substrate CNC FOTS Dried at RT for 15 min 163 [64] Wood substrate SiO 2 HDTMS Sprayed for 2 s under pressure of 42 psi 151.8 [65] Wood substrate SiO 2 N-Boroxine-PDMS 0.24 MPa at a distance of 12 cm 160.9 [66] Wood substrate PDVB NTs, SiO 2 PFS 0.3-0.…”

“…When the spray-coating method is used for the preparation of SHWSs, it is supposed to simultaneously form hierarchical roughness and low-energy surfaces. After a curing and/or drying process (i.e., the evaporation of solvents), the dispersion of the desired solutions can be applied on the wood substrate to form superhydrophobic coatings [14,[60][61][62][63][146][147][148]. In addition, the thickness of superhydrophobic coatings can be easily adjusted by many factors, including the concentration of dispersion [64], the pressure of spray gun [149], the spraying time [65], the repeated times [66], the distance between wood substrate and spray gun [67] and the drying temperature [68].…”

Synthesis of reticular long-carbon-chain polysiloxane and its hydrophobic modification of phosphogypsum-based materials

“…The preparation of high-strength and high-wear-resistance surface hydrophobic coatings remains a challenge. 14,15 Polysiloxanes can not only be used to prepare surface hydrophobic coatings but also impart overall hydrophobicity to phosphogypsum-based materials by internal mixing. Chen et al 16 prepared flue-gas desulfurization gypsum blocks using polymethyl hydrosiloxane as a waterproofing and weatherproofing agent and fly ash as a mineral admixture.…”