Efficient Shaping of Cellulose Nanocrystals Based on Allomorphic Modification: Understanding the Correlation between Morphology and Allomorphs.

Cellulose nanocrystals (CNC) are green, safe, and renewable nanomaterials with a variety of excellent performances but their morphologies are notoriously difficult to control as this is unfavorable to the diversification of the end products. Allomorphic conversion plays an important role in diversifying the morphology of CNC. However, this further complicates the prediction, design, and control of the geometric dimensions of CNC.

In vitro gastrointestinal digestibility of corn oil-in-water Pickering emulsions stabilized by three types of nanocellulose.

The effect of three nanocellulose (various in crystalline allomorph and morphology) on lipid in vitro gastrointestinal digestibility was investigated. Corn oil-in-water emulsions were prepared by CNCs-I, CNCs-II and CNFs respectively. The variations of droplets diameter D[4,3], zeta potential, and microstructure were measured during gastrointestinal digestion (mouth, stomach and small intestine), and the free fatty acid (FFA) released in the small intestine phase were examined.

Residual lignin in cellulose nanofibrils enhances the interfacial stabilization of Pickering emulsions.

Lignocellulose nanofibrils (LCNF) were used to prepare oil-in-water Pickering emulsions and to assess the role residual lignin in interfacial stabilization. Two LCNF fractions of similar morphology (length ∼700 nm and width ∼8 nm) and structure (polymorphism and crystallinity) were obtained by microfluidization of fibers obtained by hydrothermal treatment of wood with a recyclable organic acid. The LCNF with higher residual lignin was less hydrophilic and, correspondingly, performed better as Pickering stabilizer, producing emulsions of smaller droplet size and higher resistance to creaming.

Crystalline stability of cellulose III nanocrystals in the hydrothermal treatment and NaOH solution.

To better understand the system and conversion of cellulose allomorphs, cellulose III nanocrystals (CNC-III) were used to investigate the crystalline stability of cellulose III in the hydrothermal condition and a lower concentrated NaOH-water system. It was shown that HO or alkali played an important role in the process of polymorphic transformation. The CNC-III allomorph turned back to cellulose I with an extremely low crystallinity (∼4.

Acetylated cellulose nanocrystals with high-crystallinity obtained by one-step reaction from the traditional acetylation of cellulose.

One-step reaction instead of two-step or multi-step reaction is simple and feasible to prepare the acetylated cellulose nanocrystals (ACNCs). Herein, a common and moderate one-step reaction for obtaining the acetylated cellulose nanocrystals (ACNCs) with high-crystallinity via traditional acetylation of cellulose is first proposed. Morphology property analysis indicates that ACNCs with a rod-like structure have a length of 21-140 nm and a width of 12-20 nm.

Cellulose nanocrystals (CNCs) with different crystalline allomorph for oil in water Pickering emulsions.

In recent years, nanocelluloses have attracted a lot of interests as promising stabilizers for Pickering emulsion particularly in food, cosmetics and pharmaceutics industries. In this work, two cellulose nanocrystals (named CNCs-I and CNCs-II) with different crystalline allomorph were investigated as stabilizers for oil-water Pickering emulsion. CNCs were prepared by sulfuric acid hydrolysis of unmodified and mercerized microcrystalline cellulose (MCC), respectively.