Luminescent and Hydrophobic Wood Films as Optical Lighting Materials

Abstract

Most materials used for optical lighting applications need to produce a uniform illumination and require high mechanical and hydrophobic properties. However, they are rarely eco-friendly. Herein, a bio-based, polymer matrix-free, luminescent, and hydrophobic film with excellent mechanical properties for optical lighting purposes is demonstrated. A template is prepared by turning a wood veneer into porous scaffold from which most of the lignin and half of the hemicelluloses are removed. The infiltration of quantum dots (CdSe/ZnS) into the porous template prior to densification resulted in almost uniform luminescence (isotropic light scattering) and could be extended to various quantum dot particles, generating different light colors. In a subsequent step, the luminescent wood film is coated with hexadecyltrimethoxysilane (HDTMS) via chemical vapor deposition. The presence of the quantum dots coupled with the HDTMS coating renders the film hydrophobic (water contact angle ≈ 140°). This top-down process strongly eliminates lumen cavities and preserves the orientation of the original cellulose fibrils to create luminescent and polymer matrix-free films with high modulus and strength in the direction of fibers. The proposed optical lighting material could be attractive for interior designs (e.g., lamps and laminated cover panels), photonics, and laser devices.

Antiviral/antibacterial biodegradable cellulose nonwovens as environmentally friendly and bioprotective materials with potential to minimize microplastic pollution

“…The slight reduction of hydrophobicity is due to the hydrophilic nature of PHMG and NEO, thus further demonstrating the presence of such antimicrobial chains or groups on the surface of CNNWs. Since the water absorption rate can be indirectly represented by the reduction of WCA as a function of time ( Fu et al, 2020 ), it can be seen from Fig. 3 j(iv), j(v) that the reduction is higher for CNWs-CI-PTB-PHMG (10.0° over 180 s) than that of CNWs-CI-PTB-NEO (3.4° over 180 s), which may be attributed to the higher amount of PHMG grafted (3.44%) in comparison to the NEO (2.70%).…”

Review of Functional Treatments for Modified Wood

“…One common treatment seen in many of the nanotechnology based systems is the reaction of wood with organosilanes. Several have already been mentioned in this review for their ability to assist in grafting of the treatment [17,80,109], or to protect the treatment once in situ [111][112][113]. Silanes are also used in the functionalisation of nanoclays, to enhance their compatibility with the intended polymer matrix, or to promote binding of active substances.…”

Sustainable Wood Nanotechnologies for Wood Composites Processed by In-Situ Polymerization

“…Filling the lumen with a polymer matrix, see Figure 3A, improves mechanical properties compared with wood (Jungstedt et al, 2020). Densification methods show that strong, anisotropic, homogenous materials can be made from delignified substrates (Yano, 2001;Zhu et al, 2017;Song J. et al, 2018;Frey et al, 2018;Fu et al, 2020;Li et al, 2020). Resin impregnation of the lumen porosity in delignified substrates reduces moisture sensitivity and improves mechanical performance.…”