Luminescent and Transparent Wood Composites Fabricated by Poly(methyl methacrylate) and γ-Fe₂O₃@YVO₄:Eu³⁺ Nanoparticle Impregnation

Abstract

Natural wood is functionalized using the index matching poly­(methyl methacrylate) (PMMA) and luminescent γ-Fe2O3@YVO4:Eu3+ nanoparticles to form a novel type of luminescent and transparent wood composite. First, the delignified wood template was obtained from natural wood through a lignin removal process, which can be used as a support for transparent polymer and phosphor nanoparticles. Then, the functionalization occurs in the lumen of wood, which benefits from PMMA that fills the cell lumen and enhances cellulose nanofiber interaction, leading to wood composites with excellent thermal properties, dimensional stability, and mechanical properties. More importantly, this wood composite displays a high optical transmittance in a broad wavelength range between 350 and 800 nm, magnetic responsiveness, and brightly colored photoluminescence under UV excitation at 254 nm. The unique properties and green nature of the luminescent wood composite have great potential in applications including green LED lighting equipment, luminescent magnetic switches, and anti-counterfeiting facilities.

Large‐Size Transparent Wood for Energy‐Saving Building Applications

“…[23] As ah ighly transparent thermosetting resin, the refractive index of polymer PMMA is about1 .5. [17] However, there is aslight difference in transmittanceo ft he transparent fiber wood (92 AE 2%)m ade from these two species. However,i ts howed unsatisfactory transparency at at hickness of 2mmo rm ore. [15] As shown in the image (at the top right corner in Figure 1), the transparent fiber wood has exceptional transparency even with athickness of 5mm.…”

“…[11] Recently,d ifferent types of cellulose from various sourcesw eret ested to prepare transparent materials, such as bacterial or tunicate. [17] Hu and co-workersf ound that an 18 %i ncrease in energy conversion efficiency of the transparentw ood could be achieved by coating the surface of GaAs thin film solar cellso wing to the active light scattering and increase in adsorption of light within the solar cell. [14] The transparent wood was mainly fabricated by removing light-absorbing substancesa nd introducing ar efractive indexmatching polymer.…”

“…[14][15][16][17][18][19][20][21][22] The large-size transparent woodw as obtained by infiltrating the prepolymerized methyl methacrylate( MMA) solution into delignified wood fibers rather than the intact wood template. [14][15][16][17][18][19][20][21][22] The large-size transparent woodw as obtained by infiltrating the prepolymerized methyl methacrylate( MMA) solution into delignified wood fibers rather than the intact wood template.…”

“…Luminescent transparent wood offers diverse applicationsf or the preparation of the green LED lighting tools, luminescentm agnetic switches, and anti-counterfeiting facilities. [17] Hu and co-workersf ound that an 18 %i ncrease in energy conversion efficiency of the transparentw ood could be achieved by coating the surface of GaAs thin film solar cellso wing to the active light scattering and increase in adsorption of light within the solar cell. [18] Lang et al constructed electrochromic devicesb ased on transparent wood, showingt he possibility to use these devices for energysaving, smart windows.…”

“…[20] Thick or large-size transparent wood is highly desirable for practical applications.I np revious studies, however, the reported transparent wood samples were smalla nd of low thickness. [14][15][16][17][18][19][20][21][22] This is mainly because the preparation of transparent wood requires intact wood as the substrate, whereas largesized substrates are very susceptible to breakage during delignification. Lignin can be mainly found in the corners of wood cells and middle lamella, which are the key substances connectingt he wood cells.…”