3D Printable Hybrid Gel Made of Polymer Surface-Modified Cellulose Nanofibrils Prepared by Surface-Initiated Controlled Radical Polymerization (SI-SET-LRP) and Upconversion Luminescent Nanoparticles

Abstract

A cellulose nanofibril-based hybrid gel material was developed by grafting the polymerized stearyl acrylate (PSA) and upconversion nanoparticles (UCNPs) onto cellulose nanofibrils (CNFs) via Cu0-mediated radical polymerization (SET-LRP) to create a highly cross-linked CNF system. A two-step strategy was exploited to surface-exchange the ligand of the UCNPs from a hydrophobic ligand (oleic acid) to a hydrophilic small-molecule ligand (2-acrylamido-2-methyl-1-propanesulfonic acid, AMPS) and therefore be suitable for SET-LRP. The characteristics and properties of the hybrid material (UCNP-PSA-CNF) were monitored by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), rheology, X-ray diffraction (XRD), and microscopic analysis. Those characterization techniques prove the efficient modification of the CNF, with the presence of 1.8% UCNPs. The luminescence measurement was carried out using a homebuilt confocal microscope with a 980 nm laser source. The nanostructure of UCNPs and their incorporated CNF species were measured by small-angle X-ray scattering (SAXS). In addition, this CNF-based hybrid gel has decisive rheological properties, such as good viscoelasticity (loss tangent was below 0.35 for the UCNP-PSA-CNF gel, while the PSA-CNF gel reached the highest value of 0.42), shear-thinning behavior, and shape retention, and was successfully applied to three-dimensional (3D) gel printing throughout various 3D print models.

Multifunctional Cellulose Nanofibrils–GdF3 Nanoparticles Hybrid Gel and Its Potential Uses for Drug Delivery and Magnetic Resonance Imaging

“…In this study, we employed a simplified model compared to our previous work . The model is described by eq I ( q ) = A 1 · F ( q ) + A 2 nobreak0em0.1em⁡ exp ( − false( q − q 0 false) 2 2 σ 2 ) + B where A 1 and A 2 denote scale factors, F ( q ) denotes the Guinier–Porod model from Hammouda, B denotes the background, and q 0 and σ are the maximum and standard deviation of the Gaussian function, respectively.…”

“…In our previous studies, modified CNF gels with a cross-linked network exhibited enhanced rheological properties, such as viscose flow, yield stress and shape retention properties, making them suitable for 3D gel printing. 15,19 In this study, we also measured key rheological parameters with the GdF 3 −PSA cross-linked CNF gel and attempted to use the gel to create 3D-print models.…”

“…In this study, we employed a simplified model compared to our previous work. 19 The model is described by eq 1 i k j j j j j j y { z z z z z z…”

“…14 In our recent works, 15−17 we have shown that the CNF surface hydroxyls can be chemically modified to act as a radical polymerization initiator for the Cu 0 -mediated single electron transfer living radical polymerization (SET-LRP), introduced by Percec et al 18 SET-LRP is a robust polymerization technique as the reaction can be conducted in a relatively mild condition and polymerize vinyl monomers in a broad range, with full control on the grafted polymeric chain length. 18 We employed this powerful technique and demonstrated a series of approaches to cross-link polymer-grafted cellulose nanofibrils with various inorganic nanoparticles based on SET-LRP, therefore creating different CNF-based hybrid materials with enhanced mechanical properties and unique characteristics such as UV-blocking, 15 NIR absorption, 19 and electrochemical properties. 20 Gadolinium (Gd) is a rare-earth element from the lanthanide series that is widely utilized as a positive contrast agent (CA) in magnetic resonance imaging (MRI) systems.…”

Exploration of Variable Solvent Directed Self-Healable Supramolecular M(II)-Metallogels (M = Co, Ni, Zn) of Azelaic Acid: Investigating Temperature-Dependent Ion Conductivity and Antibacterial Efficiency

“…hydrogen bonding interaction, van der Waals forces, dipole–dipole, charge transfer, π–π stacking, etc., are established in literature. − Integration of metal ion with the gelators proposes a noteworthy platform to functionalize soft materials with added superior beneficial functionalities . Few celebrated practical applications of gels such as nonlinear optics, , artificial light-harvesting systems, , molecular sensing, , biomedical applications, drug delivery, − tissue engineering, , cell imaging, antibacterial and antifungal activity, − 3D printing, magnetism, , catalysis, , electronics, − light emitting diodes, biotechnology, , etc. are recognized in the scientific domain.…”