Effects of Solvent Polarity on Nanostructure Formation of Spray-Dried TEMPO-Oxidized Cellulose Nanofiber Particles

Abstract

One of the main challenges in practical applications of nanocellulose-based particles is the maintenance of their high surface area and chemical properties during particle formation in the drying process. In this study, we report the preparation of nanostructured 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO)-oxidized cellulose nanofiber (TOCN) particles via a spray-drying process without changing their chemical functionalization. The physicochemical properties of TOCN particles prepared by various types and concentrations of organic solvents were investigated. The resulting particles possessed a high ζ-potential value (−51 to −63 mV). We found that the formation of the porous structure could be realized by controlling the solvent polarity, which effectively increased the surface area to 222 m2/g and led to a good adsorption capacity for macromolecules such as lysozyme protein (>3200 mg/g). These results show that this method has a wide range of potential applications, e.g., drug delivery agents, adsorbents, encapsulation, and composite technologies.

Controlling the Magnetic Responsiveness of Cellulose Nanofiber Particles Embedded with Iron Oxide Nanoparticles

“…This finding correlates with those of previous studies. 23 When a precursor solution containing Fe 3 O 4 NPs with a mass ratio of 0.1 to TOCN was sprayed, spherical particles with an average diameter of 2.02 μm were obtained, as depicted in Figure 2b-i. Fiber entanglement was observed on the TF-0.1 surface (Figure 2b-ii), which was identical to the observation for TOCN (Figure 2a-ii).…”

“…TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl)-oxidized cellulose nanofiber (TOCN) is a notable futuristic environmentally friendly nanomaterial that is generated by the controlled oxidation of cellulose by TEMPO. , In this oxidation process, carboxyl groups are added to the cellulose surface to yield highly charged nanofibers and individual nanofibers with notable intrinsic properties. − TOCN materials exhibit a high aspect ratio, − exceptional mechanical strength, − and significant surface area, − highlighting their suitability for a wide range of applications. These materials exhibit application potential in various fields, serving as constituents in composite materials, ,− modifiers in rheology, − carriers for bioactive agents, − and emerging green materials in novel fields. − …”

“…Further, the burgeoning field of nanostructuring technology for advanced materials has gained significant attention because of its property enhancement and promising applications. − Various methods, such as coprecipitation and spraying, have been employed to obtain functional nanostructured particles . Specifically, the spray-drying method is widely recognized for its ability to produce microsized particle clusters with high specific surface areas (SSAs) from nanosized material. − Our research group has a great history of designing and producing functionalized nanostructured TOCN in powdered form (TOCN particles) by spray drying method. ,,− These particles exhibit advantageous properties, including ease of handling, storage, and transport as well as high SSA, while retaining the outstanding inherent characteristics of TOCN. TOCN particles exhibit abundant sites for electrostatic interaction, and these sites impart them with exceptional high-speed and efficient adsorption capabilities.…”

Multifunctional, Hybrid Materials Design via Spray‐Drying: Much more than Just Drying

“…The self-assembly of building blocks, such as nanoparticles and molecules within a single droplet upon solvent evaporation [8,15] can produce a variety of compositions (e.g., single-component, [16] multi-component, [17,18] inorganic-organic hybrid, [19] metal oxide hybrid [20,21] ) and structures (e.g., solid, [22] hollow, [23] core-shell [23] ) with unique properties and potential applications. Recently, many types of unique building blocks such as nanofibers, [24] nanorods, [25] and metal-organic frameworks (MOFs) [26,27] have become available and offer potential advantages. However, maintaining the distinct properties of the building blocks during self-assembly is highly important.…”

Rapid Indomethacin Release from Porous Pectin Particles as a Colon-Targeted Drug Delivery System

“…Porous particles expertly fulfill these aforementioned requirements. As porous particles are distinguished from common particles by their large surface area, − high porosity, uniform and tunable pore structure, − and well-defined inner and outer surface properties, , they are particularly suited to the delivery of drugs with fast mass transfer . For example, ammonium bicarbonate was used as the porogen to make porous microparticles from poly­(lactic- co- glycolic acid) (PLGA) by a water-in-oil-in-water double emulsion method .…”