Aqueous Counter Collision Method Research Articles

Characterization of an Amphiphilic Janus-Type Surface in the Cellulose Nanofibril Prepared by Aqueous Counter Collision.

Cellulose nanofibrils, which attract extensive attention as a bio-based, sustainable, high-performance nanofibril, are believed to be predominantly hydrophilic. This study aimed to prove the presence of an amphiphilic "Janus-type fiber surface" in water with hydrophobic and hydrophilic faces in a cellulose nanofibril (ACC-CNF) that was prepared by the aqueous counter collision method. We clarified the surface characteristics of the ACC-CNF by confocal laser scanning microscopy with a carbohydrate-binding module and congo red probes for the hydrophobic planes on the cellulose fiber surfaces and calcofluor white as hydrophilic plane probes. The results indicated the presence of both characteristic planes on a single ACC-CNF surface, which verifies an amphiphilic Janus-type structure. Both hydrophobic probes adsorbed onto ACC-CNFs for the quantitative evaluation of the degree of ACC-CNF surface hydrophobicity by Langmuir's adsorption theory based on the optimal maximum adsorption amounts for various starting raw material types.

Properties of Cellulose Nanofibers Prepared from Recycled Pulp Fiber Using the Aqueous Counter Collision Method

Properties of Cellulose Nanofibers Prepared from Recycled Pulp Fiber Using the Aqueous Counter Collision Method

Surface modification of oriented polysaccharide scaffolds using biotic nanofibers for epidermal cell culture

In this study, a novel scaffold was fabricated from nematically ordered polysaccharide molecules such as cellulose, chitin and cellulose-chitin blend (50–50%), termed as NOC, NOCh, NOC-Ch, by deposition of biotic nanofibers such as bacterial cellulose (BC) and collagen, which were prepared by aqueous counter collision method to allow the fiber width to reduce into nano-scales by high pressure impinging of aqueous suspension jets. The resultant aqueous dispersion of the nanofibers was spread over the templates using the spin coating technique and its surface morphology, roughness, strength, and hydrophobicity were characterized by atomic force microscopy followed by the tensile strength and contact angle measurements. The results indicated that, after initial deposition of BC nanofibers, the surface wettability of the scaffolds switched from hydrophobic to hydrophilic, whereas for collagen nanofibers, the surface hydrophobicity was increased. Repeated coating also improved the strength of the scaffold. Cell culture studies were carried out to explore the potentials of the modified scaffolds using the normal human epidermal cells. The results showed that the number of nanofiber coating cycles and surface morphology on the scaffolds played a role in cell elongation and its morphology. Particularly in this study, we have focussed on the changes in the morphogenesis such as cell adhesion and cell size grown on 1, 3 and 5 times coated scaffolds. The result indicated that the morphological changes depending on the coating nanofibers in the surface of scaffolds were related to increase in the epidermal cell size and altering cell adhesion.

Fabrication of cellulose nanofiber-deposited cellulose sponge as an oil-water separation membrane

A cellulose sponge was fabricated through xanthation to dissolve cellulose, and heating to regenerate the cellulose solution. The obtained cellulose sponge showed good physical strength with resilient ratio and unrecoverable proportion at 60% compression stress of 42.6% and 25.7%, respectively. Bamboo-based counter collision cellulose nanofiber (MECH-CNF) prepared by the aqueous counter collision method and wood-free fiber-based 2,2,6,6-tetramethylpiperidine-1-oxyl oxidized cellulose nanofiber (TEMPO-CNF) were used to increase the hydrophilicity and underwater oleophobicity of the cellulose sponge. Oil contact angles in air and underwater were investigated to evaluate oleophobicity. The TEMPO-CNF-deposited cellulose sponge (TCNF-membrane) demonstrated higher oleophobicity underwater than MECH-CNF-deposited cellulose sponge (MCNF-membrane). Oil-water separation was tested to evaluate the possibility of water treatment applications. The flowrate of the MCNF-membrane was 3.73 × 103 L m−2 h−1 and much higher than that of the TCNF-membrane at 166 L m−2 h−1, both at separation efficiency levels higher than 99% by gravitational force alone.

Difference between bamboo- and wood-derived cellulose nanofibers prepared by the aqueous counter collision method

Bamboo pulps whose crystalline and hierarchical structures differ from those of wood pulps were subjected to the aqueous counter collision (ACC) method, which makes it possible to overcome interfacial interactions between cellulose molecules in order to produce cellulose nanofibers (CNFs) and hence highlights differences between surface properties. At first, the CNFs derived from both bamboo and wood were compared in studies of the sedimentation behavior of 0.05% (w/w) aqueous CNF dispersions. Then, changes in mechanical properties of CNF sheets under various humidity conditions, as well as the CNF emulsion droplets formed by mixing with n-hexane, both of which were prepared from aqueous CNF dispersions, were examined. These investigations focusing on the interaction of CNFs with water indicated totally different inherent nature in the surface properties between bamboo and wood CNFs, which were prepared by the ACC method. Moreover, the different character in the two CNF emulsion droplets also indicates that the surface on bamboo-derived CNFs prepared by this method was likely to exhibit more hydrophobic properties than wood CNFs without any chemical modification.

Preparation of Aqueous Carbon Material Suspensions by Aqueous Counter Collision

Abstract Aqueous dispersions of hyperhydrophobic fullerene C60, multiwalled carbon nanotubes, and graphite were prepared. This was achieved by the aqueous counter collision method, designed to fabricate nanofibers and nanoparticles. Dispersions of carbon materials could be prepared by collision from two high-speed water jets. The dispersed states of the materials differed significantly, presumably because of the different nanoscale configurations of the materials.

Preparation of Single Cellulose Nanofibers Dispersed in Water Using Aqueous Counter Collision Method

Preparation of Single Cellulose Nanofibers Dispersed in Water Using Aqueous Counter Collision Method