Gradient heating activated ammonium persulfate oxidation for efficient preparation of high-quality chitin nanofibers.

APS is a cheap and eco-friendly oxidant which enables one-step extraction of nanochitin (NCh) from fishery wastes. However, it is challenging to improve the preparation efficiency and NCh quality simultaneously, owing to the uneven or uncontrollable oxidation. Herein, we propose a simple and controllable way to isolate chitin nanofibers (ChNFs) from squid pen by gradient heating activated (GHA)- ammonium persulfate (APS) oxidation.

Liquid-crystalline assembly of spherical cellulose nanocrystals.

Rod-shaped cellulose nanocrystals (CNCs), also called cellulose nanorods (CNRs), possess anisotropic properties that allow for their self-organization into chiral nematic liquid crystals. Interestingly, spherical cellulose nanocrystals (cellulose nanospheres, CNSs) have also been shown to form a chiral liquid-crystalline phase in recent years. Herein, to understand how the similar assembly takes places as particle dimension changes, the organization features of CNSs were investigated.

Effects of the surface chemical groups of cellulose nanocrystals on the vulcanization and mechanical properties of natural rubber/cellulose nanocrystals nanocomposites.

Cellulose nanocrystals (CNCs), as the promising reinforcing fillers in the rubber industry, their surface chemical groups have vital effects on the vulcanization kinetics, cross-linking densities, and mechanical properties of rubber composites. Herein, CNCs with acidic carboxyl (CCA) and alkaline amino groups (CCP) were produced by modifying the sulfonic CNCs (CCS) in environment-friendly ways. Studies found the CCS and CCA with acid groups have obvious inhibiting effects on the vulcanization of natural rubber (NR), while CCP with alkaline amino groups accelerates the vulcanization of NR.

Tuning liquid aggregation of zwitterionic chitin nanocrystals by graphene oxide planar catchers via electrostatic regulation.

As important structural units, biomass nanomaterials have exhibited great potentials to construct high-performance macroscopic materials for broad applications by liquid assembly. However, the liquid aggregation of nanomaterials was less investigated. Here, we demonstrate that the one-dimensional (1D) zwitterionic chitin nanocrystals (ZChNCs) can be reversibly captured and released by two-dimensional (2D) planar catchers of graphene oxide (GO) sheets.

Electric Field-Induced Assembly and Alignment of Silver-Coated Cellulose for Polymer Composite Films with Enhanced Dielectric Permittivity and Anisotropic Light Transmission.

Multifarious wearable electronics with flexible touch screens have been invented for extensive outdoor activities. One challenge associated with these wearable electronics is the development of materials with both high dielectric permittivity and anisotropic light transmission, which is responsible for high touch sensitivity and screen peep-proof protection, respectively. Herein, we demonstrated a scalable approach for assembling and aligning anisotropic cellulose in a polymer matrix through the thickness direction via the assistance of an electric field to address this challenge.

Modified ammonium persulfate oxidations for efficient preparation of carboxylated cellulose nanocrystals.

Ammonium persulfate (APS) was able to produce carboxylated cellulose nanocrystals (CNCs-COOH) directly from the raw materials of cellulose. However, the industrial production of CNCs-COOH by this method is obstructed by the lower preparation efficiency. Herein, by the activation via N,N,N',N'-tetramethylethylenediamine (TMEDA) and ultrasonic assisted disintegration, modified APS method to extract CNCs-COOH from pulp was presented.

Tough, Ultralight, and Water-Adhesive Graphene/Natural Rubber Latex Hybrid Aerogel with Sandwichlike Cell Wall and Biomimetic Rose-Petal-Like Surface.

Graphene aerogel (GA) as a rising multifunctional material has demonstrated great potential for energy storage and conversion, environmental remediation, and high-performance sensors or actuators. However, the commercial use of GA is obstructed by its fragility and high cost. Herein, by a simple stirring-induced foaming of the mixed aqueous solutions of natural rubber latex (NRL) and graphene oxide liquid crystal (GOLC), we obtained tough, ultralight (4.

Natural rubber bio-nanocomposites reinforced with self-assembled chitin nanofibers from aqueous KOH/urea solution.

Rigid chitin nanofibers (ChNFs) self-assembled from dilute α-chitin/KOH/urea aqueous solution were utilized as 1D filler to reinforce soft natural rubber (NR). The prepared ChNFs suspension has good compatibility with natural rubber latex (NRL) and thus showing favorable dispersibility in NR matrix at nanoscale. The bio-nanocomposites were fabricated by casting and evaporating the pre-mixed NRL/ChNFs suspensions with different ChNFs loadings.

Ultrafine and carboxylated β-chitin nanofibers prepared from squid pen and its transparent hydrogels.

TEMPO-mediated oxidation has been successfully used to prepare carboxylated chitin nanofibers (ChNFs) with purified chitins originating from the outer shells of crab and shrimp (α-form) or tubeworm (β-form). However, the method for obtaining carboxylated ChNFs with squid pen chitin (hydrated β-form) has not been developed yet. It might be due to the existence of the small amount of partial deacetylation (DD ≈ 9%) in the squid pen β-chitins.

Effect of surface chemistry on the dispersion and pH-responsiveness of chitin nanofibers/ natural rubber latex nanocomposites.

Chitin nanofibers (ChNFs) have emerged as a rising nanomaterial due to their excellent mechanical properties, biocompatibility and biodegradability etc. Herein, carbonylated ChNFs (C-ChNFs) and zwitterionic ChNFs (NC-ChNFs) decorated with both amino (-NH) and carboxyl (-COOH) groups were used to prepare ChNFs/natural rubber (NR) nanocomposite films by dip molding method, respectively. The results showed that C-ChNFs had better dispersion than that of NC-ChNFs in NRL matrix.

Influence of Branched Polyester Chains on the Emission Behavior of Dipyridamole Molecule and Its Biosensing Ability.

Toward the development of the smart biosensing drug carrier, integration of dye molecules with polymeric chain has been an emerging method in recent years. In this perspective, dipyridamole (Dip)-based branched poly(l-lactide) (PLLA) and branched polycaprolactone (PCL) have been synthesized by ring-opening polymerization. After polymerization, the influence of the polyester chains on the Dip emission behavior has been studied systematically in this work.

Ultralight, Superelastic, and Fatigue-Resistant Graphene Aerogel Templated by Graphene Oxide Liquid Crystal Stabilized Air Bubbles.

Graphene aerogel (GA) has attracted great attention due to its unique properties, such as ultralow density, superelasticity, and multifunctionality. However, it is a great challenge to develop superelastic and fatigue-resistant GA (SFGA) with ultralow density because it is generally contradictory to improve the mechanical properties with reducing density of GA. Herein, we report a simple and efficient approach to prepare ultralight SFGA templated by graphene oxide liquid crystal (GOLC) stabilized air bubbles.

Green and facile surface modification of cellulose nanocrystal as the route to produce poly(lactic acid) nanocomposites with improved properties.

In this study, lactic acid monomer or dimer is grafted onto CNC by a simple esterification reaction. The quantitative solid-state C NMR spectrum suggests that more than 87% of all the available OH groups on the surface of CNC are substituted by lactic acid. Such modified CNC (CNC-g-LA) exhibits excellent thermostability and nano-sized dispersion in chloroform.

One-pot synthesis of graphene/chitin nanofibers hybrids and their remarkable reinforcement on Poly(vinyl alcohol).

Novel hybrid nanomaterials composed of graphene and chitin nanofibers (ChNFs) were successfully prepared by one-pot ball milling. Under strong shear and collision force of ball milling, graphite was exfoliated to mono-layer or few-layer graphene with the assistance of chitin nanofibers. Unexpectedly, the hybridization of exfoliated graphene and ChNFs was realized simultaneously.

Simultaneous improvement of thermal stability and redispersibility of cellulose nanocrystals by using ionic liquids.

Cellulose nanocrystals (CNCs) are predominantly obtained by the traditional sulfuric acid hydrolysis process. However, as-prepared CNCs powder features low thermal stability and poor redispersibility due to the existence of sulfonate groups and the hydrogen bond interaction among particles. Herein, by mixing the ionic liquid [BMIm][BF] with freshly prepared CNCs without dialysis through a simple rotary evaporate procedure, the simultaneous improvement of thermal stability and redispersibility of CNCs has been achieved.

Modifying Mechanical, Optical Properties and Thermal Processability of Iridescent Cellulose Nanocrystal Films Using Ionic Liquid.

Iridescent films formed from the self-assembly of cellulose nanocrystals (CNCs) are brittle and difficult to handle or integrate within an industrial process. Here we present a simple approach to prepare iridescent CNC films with tunable pliability and coloration through the addition of ionic liquids (ILs) of 1-allyl-3-methylimidazolium chloride (AmimCl) as plasticizers. By using the undried CNC film as a filter membrane and ILs solution as a leaching liquid, it was found that the filtration process made ILs uniformly interpenetrate into CNC film due to the strong ionic interaction between CNC and AmimCl.

Study on π-π Interaction in H- and J-Aggregates of Poly(3-hexylthiophene) Nanowires by Multiple Techniques.

There has been intense interest in understanding the self-assembled structure of conductive polymer nanowires due to the potential application in photovoltaics area. In the present study, free-standing poly(3-hexylthiophene) (P3HT) thin films consisting of H-aggregated and recently reported J-aggregated nanowires (NWs) were respectively prepared by the vacuum filtration method. The microstructure differences of both samples were studied in detail by combining the multiple techniques, i.

Chemical structure and interlayer distance correlation of graphite oxide in the heating process as revealed by in situ Fourier transform infrared spectroscopy and wide-angle X-ray diffraction techniques.

The thermal reduction behavior of graphite oxide (GO) film in an air atmosphere during a continuous heating process was monitored in situ using temperature-dependent infrared (IR) spectroscopy and synchrotron radiation wide-angle X-ray diffraction (WAXD) techniques. The results show that most of the water adsorbed by the GO sheets is removed by heating them to 130 °C. The dehydration process leads to a slight decrease of the interplane distance of the GO sheets.

A green and facile approach for the synthesis of water-dispersible reduced graphene oxide based on ionic liquids.

A green and facile route for producing reduced graphene oxide based on ionic liquids has been proposed, in which the as-prepared graphene can be redispersed stably in water (up to 0.6 mg mL(-1)) after being made into a flow-directed solid film.

Physical aging enhanced mesomorphic structure in melt-quenched poly(L-lactic acid).

The structural evolutions and kinetics of melt-quenched poly(L-lactic acid) (PLLA) during the process of isothermal physical aging below the glass transition temperature (T(g)) were investigated by time-resolved infrared spectroscopy. The results show that local ordered structure is developed with aging time. Such local ordered structure shows the same characteristic band at 918 cm(-1) as that of the mesomorphic structure formed during the unaxially drawn process of PLLA from the glassy state.

Molecular weight dependence of the poly(L-lactide)/poly(D-lactide) Stereocomplex at the air-water interface.

The molecular weight dependence of poly(L-lactide)/poly(D-lactide) (PLLA/PDLA) stereocomplex behavior at the air-water interface was studied by surface pressure-area (pi-A) isotherms and atomic force microscopy (AFM). It was found that the compression-induced sterecomplexation of a PDLA/PLLA equimolar blend with high molecular weight (M(w) = 1 x 10(6) and 9.8 x 10(5), respectively) could occur at the air-water interface.

Initial crystallization mechanism of isotactic polystyrene from different States.

The isothermal crystallization processes of isotactic polystyrene at 160 degrees C from different initial states (quenched glassy state and melt state), i.e., cold- and melt-crystallization processes, have been investigated by infrared (IR) and generalized two-dimensional (2D) IR correlation spectroscopy.

On the alpha --> beta transition of carbon-coated highly oriented PVDF ultrathin film induced by melt recrystallization.

Poly(vinylidene fluoride) (PVDF) is one of the polymers which exhibit pronounced polymorphic crystalline forms, depending on crystallization conditions. Four different crystalline modifications, i.e.