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48 TECHNOLOGY SEP/OCT 2024 FDM ASIA | www.fdmasia.com

This approach was further implemented, using rare-earth
strontium aluminium oxide nanoparticles dispersed in the
monomer (methyl acrylate) employed for the infiltration of
basswood slabs, or vacuum-impregnating basswood slices

with a UV-curable resin—namely, a mixture of poly(urethane
acrylate), poly(ester acrylate), epoxy acrylate, and acrylamide
morpholine—containing a reactive red X-3B dye.
Within the goals of sustainability and environmental
protection, one of the current most challenging and impacting
issues refers to the management and removal of microplastics
The possibility of using delignified balsa wood nanopores from the aquatic environment, as they represent a severe
as a confinement template for activating the room-temperature threat not only to aquatic organisms but also to human health.
phosphorescence of organic dyes was thoroughly demonstrated In this context, Liu and co-workers assessed the possibility

by Zhu and co-workers. of using cellulose nanofiber-coated delignified balsa wood as a
More specifically, the delignified template gave rise to a green, effective, renewable filter for the removal of microplastics.
three-dimensional nanostructure bearing stable H-bonds and To this aim, balsa wood chips underwent delignification
a stiff network, which accounted for the suppression of the through three different methods (i.e., employing a deep eutectic
nonradiative transition of the selected organic dye molecules solvent made of lactic acid and choline chloride, using NaClO2,
(namely, gallic and ellagic acid, quercetin, and vanillin), facilitating or a solution of Na2SO3 and NaOH).
the room-temperature phosphorescence emission. The mechanical properties and the porosity of the delignified

Further, the authors demonstrated the appropriateness of balsa wood were optimised. Then, the delignified wood was
the wood-based organic room-temperature phosphorescent dipped in suspensions of cellulose nanofibers at different
composite materials for the fabrication of 3D-printed high- loadings (namely, 0.25, 0.50, 0.75, and 1.0 wt%) and finally
precision devices, potentially suitable for data encryption and crosslinked with CaCl2 solutions.
anticounterfeiting. The formation of a film of cellulose nanofibers on the
In a further research effort, Lu and co-workers exploited delignified wood surface was responsible for the high observed
delignified balsa wood for preparing colourful room-temperature efficiency in filtering and removing polystyrene microplastics: in
phosphorescence materials that may find potential applications particular, when the average particle size of these microplastics
as afterglow windows, anticounterfeiting labels, and time was 25 μm, the use of 10 mm thick delignified wood, coated

delay lightings. In particular, after delignification in an acidic in a 0.5 wt% cellulose nanofiber suspension and subsequently
aqueous sodium chlorite solution, the resulting wood scaffold crosslinked in one mol/l CaCl2 solution, accounted for a
was infiltrated with poly(vinyl alcohol) solutions containing removal efficiency as high as 96 percent and a high filtration
arylboronic acids with different π conjugations. rate (measured flux: 1146 L/m2-h).
The concurrent stiffening action provided by the formed At present, the multifunctionality of transparent wood is
H-bonds and the B-O covalent bonds ensured an ultralong emerging as a demanding topic, aiming to widen its potential
lifetime of 2.13 s and a highly stable room-temperature applications. This challenge was taken up by Li et al., who

phosphorescence emission, together with 90 percent optical succeeded in producing bio-based transparent wood exhibiting
transmittance and high tensile strength (about 150 MPa). flame retardance, mechanical strength, and phase change