Regenerated Cellulose Microgel: A Promising Reinforcing Agent and Gelator for Soft Matter

Abstract

Unlike one-dimensional (1D) cellulose materials, such as cellulose nanofibers (CNFs), cellulose nanowhiskers, or microfibrillated cellulose, three-dimensional (3D) cellulose microgels have a multiscale structure composed of microscale particle size and nanoscale porous network. The hydrophilicity and microscale particle size enable homogeneous dispersion of microgels in water and render unique rheology property. While the nanoporous network of microgels assembled by the cellulose nanofiber allows diffusion and in situ polymerization of small molecules to form interpenetrating polymer network. Therefore, there is a huge potential for cellulose microgels as reinforcing agent and gelator for soft matter. In this work, as a proof of concept, cellulose microhydrogels (CMH) with narrow particle size distribution and tunable microstructure are prepared by applying high-speed shearing to chemically cross-linked regenerated cellulose macrogel. The as prepared microgels can be homogeneously dispersed in water, and form interpenetrating network with in situ polymerized polyacrylamide (PAM). This interpenetrating behavior between microgels and PAM accelerates the gelation process. Compared to CNFs reinforced PAM hydrogel, CMH/PAM hydrogel shows superior toughness in the compressive test with tunable mechanical properties by adjusting microstructure of microgel through tuning the cross-linking density. Cellulose microgel shows as a promising reinforcing agent and gelator for potential use in 3D printing of soft matter or as rheological modifier.

Cellulose Microbeads: Toward the Controlled Release of Nutrients to Plants

“…The analysis range was fixed between 1 and 3500 μm and the average sample measurement time was at 10 s, with averages determined by 10 measurements. The following parameters were used for the software: particle refractive index: 1.468 and dispersant (water) refractive index: 1.330 . The Mie scattering model was used within Mastersizer particle size analysis software .…”

Cellulose Microgel Toughening of Starch Nanocomposites: Exploiting the Advantages of Micro-Nanoscale Networks

“…CMs are of micrometer size and consist of nanoporous network of cellulose nanofibers (Figure ). , CM/PLS nanocomposites were prepared using the melt blending method to maintain starch as a continuous phase while dissipating energy with cellulose microgels to enhance both the strength and toughness. Individualized CNFs were employed as a control to demonstrate the advantage of the network structure of the cellulose microgel in the toughening process.…”

3D Interlayer Slidable Multilayer Nano-Graphene Oxide Acrylate Crosslinked Tough Hydrogel

“…Hydrogels have excellent potential for biomedical and bioengineering applications, but the lack of mechanical properties leads to their limitations in practical applications . The methods of strength enhancement mainly focus on the following two kinds: (1) enhancing the mechanical energy dissipation − and (2) enhancing the uniformity of polymer network distribution. , …”

“…The transformation of crosslinking sites from zero-dimensional (0D) “dots” to three-dimensional (3D) crosslinked units will provide more possibilities for the design of tough hydrogels . The hydrogel prepared from 3D polymer crosslinking units shows better mechanical energy dissipation efficiency. , Noncovalent interactions in polymer crosslinking units are destroyed and reorganized, resulting in deformation, energy dissipation, and regulation of polymer chain distribution. ,, This phenomenon enables the hydrogel polymer network to have the potential to deal with more complex and harsh application environments.…”