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ABSTRACT: Cellulose nanocrystals (CNCs) as attractive nanomaterials are widely distributed in higher plants, algae, and marine animals. Herein, three kinds of CNCs were isolated by sulfuric acid hydrolysis from cotton pulp, algae, and tunicate cotton, respectively. Their morphologies and size were characterized by scanning electron microscope and atomic force microscope. The results showed that the aspect ratio of CNCs was in the order of CNCs from cotton pulp (CCNCs) (15 ± 10) < CNCs (ACNCs) from algae (ACNCs) (18 ± 12) < CNCs from tunicate (TCNCs) (75 ± 60). The phase transitions of CNC suspensions were also determined by phase diagram and rheological experiments. Two critical concentrations from isotropic to biphasic phase (Ci) and from biphasic to anisotropic phase (Ca) were measured and calculated, indicating that CNCs with higher aspect ratio reached Ci and Ca at lower concentration. Furthermore, the critical concentrations were also checked by polarized optical microscopy measurement. This work provided important information for construction of CNCs reinforced nanocomposites and investigation of CNCs chiral nematic liquid crystals. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45702. [ABSTRACT FROM AUTHOR]

Cellulose nanocrystals are considered as promising biomass nanofillers for polymeric hydrogels, but poor interface compatibility between cellulose nanocrystals and hydrogel matrix usually reduces their reinforcement effect. Here, we reported a novel interface compatible nanocomposite hydrogel prepared by introducing quaternized tunicate cellulose nanocrystals (Q-TCNCs) into chemically cross-linked poly (acrylic acid) (PAA) networks. Q-TCNCs acted as both nanofillers and physical cross-linkers in the PAA networks, and the electrostatic interaction between the positive charges of Q-TCNCs and negative charges of PAA chains improved their interface compatibility. The nanocomposite hydrogels exhibited controllable swelling ratio and pH-sensitive swelling behaviors. The mechanical properties of hydrogels significantly increased after incorporation of Q-TCNCs. Moreover, the nanocomposite hydrogels exhibited partly recoverable ability due to the presence of reversible electrovalent bonds in the hydrogel networks. [ABSTRACT FROM AUTHOR]

• Chromatic patterns were printed with a single ink based on CNCs. • The CNCs were arranged via 3D printing and locked within the polymeric networks. • The luminance and color difference were digitally controlled by printing parameters. • The chromatic printing was facile, fast, reproducible, accurate, and scalable. • The chromatic patterns were visible only in polarized light. Cellulose nanocrystals (CNCs), a type of natural photonic crystal, have been used to develop various optical materials owing to their chiral nematic organization, renewability, sustainability, and abundance. However, scaling up the production of CNC-based photonic materials remains challenging because of their long self-assembly time, inevitable assembly defects, static optical properties, and brittle nature. To address these drawbacks, the current study introduces flexible photonic hydrogels with chromatic patterns that are 3D printed using CNC-based inks. These viscoelastic inks were composed of photopolymerizable monomers and CNCs that harbored high aspect ratios. The luminance and color difference of the patterns in the photonic hydrogels were digitally controlled by varying the printing angles and the number of layers. Furthermore, our technique was validated by printing recognizable QR codes, Tai-chi, and hydrogel color cards. The current study provides a facile, fast, reproducible, accurate, and scalable strategy for fabricating photonic hydrogels from sustainable materials with chromatic patterns visible only in polarized light, thereby demonstrating their potential use in optical devices, anti-counterfeiting applications, and information concealment and dissemination. [ABSTRACT FROM AUTHOR]

In this study, tunicate cellulose nanocrystals (TCNCs) were introduced into castor oil-based waterborne polyurethane (WPU) to prepare bio-based nanocomposites through a simple solution blending method. The effect of TCNCs content on the particle size and stability of the composite dispersions, as well as the thermophysical and mechanical properties of the composite films were studied and discussed. The unique structure and properties of TCNCs, such as high crystallinity, large aspect ratio and high modulus, not only greatly improved the storage stability of WPU, but also showed significant reinforcing/toughening effects and excellent compatibility to WPU. By drip-coating silver nanowires (AgNWs) on the surface of the composite films, the flexible strain sensors were fabricated, which showed excellent sensitivity in monitoring human movement. [Display omitted] [ABSTRACT FROM AUTHOR]