Polysaccharide based beads with unique porous structure have gained considerable interests due to their specific adsorption behaviors and biodegradability. The purpose of this paper was to develop hollow cellulose/carbon nanotubes composite beads with aligned porous structure which have potential applications in fast adsorption field. The composite beads were fabricated by ice template and freeze-drying technology. Different characterizations have proved that the carbon nanotubes and magnetic nanoparticles have been incorporated into the cellulose beads. Higher concentration of carbon nanotubes and cellulose would result in a larger diameter of the composite beads. The composite beads can effectively adsorb the methylene blue (MB). The pseudo-second-order model and Langmuir isotherm were best fitted to the adsorption. The composite beads showed a fast adsorption behavior towards MB with a t1/2 of 1.07 min obtained from pseudo-second-order model. The maximum adsorption capacity was 285.71 mg g−1 at pH 7.0. The composite beads also showed good reusability and biodegradability. We anticipate that different polysaccharides based composite beads with aligned porous structure can be obtained through the similar methods and applied in adsorption fields.

In this work, 1,3,6,8-pyrenesulfonic acid sodium salt (PTSA) was successfully synthesized via a one-step sulfonating reaction. This method is more convenient, effective and eco-friendly than the traditional one. The as-prepared PTSA exhibits pure blue fluorescence under UV light. Due to its excellent fluorescent properties and water solubility, PTSA was used to prepare water-soluble invisible inks based on hydroxyethyl cellulose (HEC) aqueous solution. Notably, the resulting inks possessed acceptable stability after being stored for 30 days. Besides, the red/green/blue fluorescent inks were obtained by adding extra pigments, all of which exhibited excellent rheology and thixotropy properties. Subsequently, various patterns, including a QR code, the logo of Wuhan University, Chinese characters and so on, were printed on non-background paper through ink-jet and screen printing, and the as-prepared materials exhibited good water solubility and outstanding fluorescence performances, indicating that the fluorescent PTSA material is a promising candidate for anti-counterfeiting applications.

Self-healable, transparent, and antifogging polysaccharide films composed of acrylamide-modified chitosan (AMCS) and alginate aldehyde (ADA) were fabricated via layer-by-layer (LBL) assembly. The Schiff base linkage formed between amino groups of AMCS and aldehyde groups of ADA was used to construct the films. Fourier transform infrared spectroscopy and X-ray photoelectron spectra revealed that the films were cross-linked through Schiff base bonds. Ultraviolet visible spectroscopy and field emission scanning electron microscope characterizations demonstrated that the films exhibited linear growth during the LBL process. The films showed a repetitive self-healing property, and the repeated damage-healing of the films was thickness-dependent. The films can heal the scratches that penetrated to the underlying substrates. Besides the excellent self-healing property, the films showed an antifogging property due to the hydrophilic nature of the two polysaccharides. The antifogging ability of the film was thickness-dependent. Also, the films could regain their transmittance and fog-resistant property after mechanical abrasion due to their self-healing capability. These self-healable and fog-resistant polymeric films have potential applications in food packaging.

In this study, hollow chitin microspheres with hierarchically porous structure were prepared for the first time through freeze-drying with alkali/urea mixture as solvent and liquid nitrogen as coagulant. The hollow structure can be facilely tuned by the concentration of chitin, freeze-drying temperature and prefreeze temperature. Higher concentration of chitin and pre-freeze temperature resulted in a thicker wall of the microspheres. This simple and template-free method can be easily extended to fabricate other hollow polysaccharide microspheres with hierarchically porous structure. The prepared chitin microspheres with excellent biological features may have potential applications in environmental treatment and biomedicine. (C) 2018 Elsevier B.V. All rights reserved.