查找使用阿拉丁产品的科研文献

Regenerated and rotation-induced cellulose-wrapped oriented CNT fibers for wearable multifunctional sensors

Changfei Jing,Weihua Liu,Huali Hao,Huagao Wang,Fanbin Meng,Denvid Lau

Recently, wearable multifunctional fibers have attracted widespread attention due to their applications in wearable smart textiles. However, stable application, large-scale production and more functions are still the greatest challenges for functional fiber devices. In this study, wearable multi-functional coaxial fibers with oriented carbon nanotubes (CNTs) were achieved for the first time coaxial wet-spinning with rotating coagulation bath. Specifically, the cellulose solution can be regenerated in the coagulation bath and the CNTs dispersion will be oriented under the rotating force. The synergy between hydrogen bonding and van der Waals interaction enhance the mechanical strength of coaxial fibers. Especially, CNTs can prevent the rotation of the cellulose chain and the bending of the glycosidic twist angle at the atomic scale as indicated by molecular dynamics (MD) simulations. When the fibers are strained, the cellulose sheath will drive the movement of CNTs, causing changes involving the effective contact area and number of conductive paths. Therefore, the high electrical resistance response change enables the as-obtained coaxial fibers to exhibit a great potential in wearable strain sensors. Furthermore, coaxial fibers can be made into electric heaters based on the Joule heating principle. The heating temperature reaches more than 160 °C within 6 s at 10 V, which is of a great value for large area flexible heaters. Besides, the coaxial fibers can further be used as temperature-sensitive devices to accurately perceive the external temperature. Therefore, the scalable synthesis of multifunctional coaxial fibers is significantly expected to provide a platform for the large-scale production of multifunctional wearable intelligent textiles.

Ultrathin Cellulose Voronoi-Nanonet Membranes Enable High-Flux and Energy-Saving Water Purification

Ning Tang,Yuyao Li,Jianlong Ge,Yang Si,Jianyong Yu,Xia Yin,Bin Ding

Creating a desirable porous membrane with high-flux and energy-saving properties for the purification of water containing submicron-sized contaminants, especially pathogenic microbes, is of great significance, yet a great challenge. Herein, we demonstrate a facile methodology to construct an innovative membrane with continuous cellulose Voronoi-nanonet structures via nonsolvent-induced phase separation. This approach enables cellulose Voronoi nanonets to tightly weld with electrospun nanofibrous substrates by controlling the solvent–nonsolvent mutual diffusion process. The resultant membranes exhibit integrated properties of small pore size (0.23 μm), high porosity (90.7%), good interconnectivity, and ultrathin thickness (∼600 nm, 2 orders of magnitude thinner than the conventional microfiltration membrane). As a result, the prepared membranes can effectively intercept submicron particles (∼0.3 μm) with robust rejection efficiency (>99.80%) and ultrahigh permeation flux (maximum of 8834 L m–2 h–1) under an extremely low driving pressure (≤20 kPa). More importantly, prominent bacterial rejection efficiency with a log reduction value (LRV) of 8.0 (overcoming the previous limitation of LRV <7) and outstanding antifouling function are also achieved for the membranes. The successful fabrication of such a versatile membrane may provide new insights into the development of next-generation high-performance separation materials for various applications.

Glycerin/NaOH Aqueous Solution as a Green Solvent System for Dissolution of Cellulose

Ke Li,Huiyu Yang,Lang Jiang,Xin Liu,Peng Lang,Bo Deng,Na Li,Weilin Xu

Dissolving cellulose in water-based green solvent systems is highly desired for further industrial applications. The green solvent glycerin—which contains hydrogen-bonding acceptors—was used together with NaOH and water to dissolve cellulose. This mixed aqueous solution of NaOH and glycerin was employed as the new green solvent system for three celluloses with different degree of polymerization. FTIR (Fourier-transform infrared), XRD (X-ray diffractometer) and TGA (thermogravimetric analysis) were used to characterize the difference between cellulose before and after regenerated by HCl. A UbbeloHde viscometer was used to measure the molecule weight of three different kinds of cellulose with the polymerization degree of 550, 600 and 1120. This solvent system is useful to dissolve cellulose with averaged molecule weight up to 2.08 × 105g/mol.Keywords:cellulose;glycerin;dissolution;green solvent;aqueous solution

A biocompatible cellulose-nanofiber-based multifunctional material for Fe3+ detection and drug delivery

Lei Wang,Hongxiang Zhu,Guotao Xu,Xudong Hou,Hui He,Shuangfei Wang

Although biomass-based materials offer several advantages as matrices for the development of multifunctional sensors, they have rarely been applied for dual-function solid colorimetric and spectrophotometric sensing. Herein, a nanoscale cellulose-nanofiber-based multifunctional material (CNF-DA) with excellent biocompatibility was prepared by grafting dopamine (DA) onto cellulose nanofibers with carboxyl groups (CNF-COOH) using an amidation reaction. Owing to the morphological diversity of as-prepared CNF-DA (e.g., a nanoscale homogeneous suspension, solid nanofibers, and an aerogel), multifunctional properties, including drug delivery, antibacterial properties, and spectrophotometric and solid colorimetric Fe3+ sensing, were realized. Solid CNF-DA exhibited excellent selectivity and sensitivity toward Fe3+ with a remarkable color change from off-white to dark green and a limit of detection (LOD) of 5 × 10−7 mol L−1. Furthermore, CNF-DA was applied as a UV spectrophotometric sensor for Fe3+ in aqueous solution with an LOD of 6.6 × 10−11 mol L−1. CNF-DA also exhibited drug delivery and antibacterial properties owing to an abundance of hydroxyl groups and the high porosity of the nanofiber. The maximum drug loading capacity of CNF-DA and the release rate of doxorubicin were 879.09 mg g−1 and 80% at pH 1.2, respectively. Thus, multifunctional CNF-DA has broad application prospects in the areas of food science and biological medicine.

Biotemplate synthesis of polypyrrole@bacterial cellulose/MXene nanocomposites with synergistically enhanced electrochemical performance

Song Quancheng,Zhan Zeying,Chen Binxia,Zhou Zehang,Lu Canhui

Polypyrrole (PPy) has received extensive attention in supercapacitor electrodes due to its promising electrochemical activity, while the poor cycling stability and densely packed structure limited its electrochemical performance. Herein, we demonstrate the fabrication of flexible and freestanding PPy@bacterial cellulose (BC)/MXene composite film with significantly enhanced electrochemical performance. PPy nanoparticles were uniformly deposited on BC nanofibers via in situ polymerization, and assembled with highly conductive MXene (Ti 3 C 2 T x ) nanoflakes through strong interfacial interactions. BC as a biological template can effectively disperse PPy nanoparticles. The intercalation of PPy@BC nanofibers into Ti 3 C 2 T x layers constructs hierarchically packed nanofibrous structure, which provides extensive accessible electrochemical active sites. Freestanding PPy@BC/Ti 3 C 2 T x (PBM) electrode exhibits superior specific capacitance (gravimetric and areal capacitance of up to 550 F g −1 and 879 mF cm −2 , respectively) and excellent capacitance retention of 83.5% after 10,000 cycles. In addition, the symmetric supercapacitor assembled by PBM papers present a high energy density of 33.1 W h kg −1 (power density of 243 W kg −1 ) and excellent capacitance retention. The elaborately designed nanostructure and PPy-Ti 3 C 2 T x hybridization make great contribution to the enhanced electrochemical performance, which provide a feasible method for the fabrication of conductive polymer-based high-performance flexible supercapacitor electrodes. Graphic abstract

Electrospinning of multifunctional cellulose acetate membrane and its adsorption properties for ionic dyes

Wenjuan Chen,Hongzhu Ma,Baoshan Xing

Electrospinning of cellulose acetate with appropriated solvent system is the most straightforward method for fabricating micro- and nanofibers. To simultaneously and effectively remove both cationic and anionic dyes, a novel cost-effective multifunctional cellulose acetate (CA) fibers membrane was prepared by electrospinning followed by deacetylation , carboxymethylation and polydopamine (PDA) coating. The adsorption properties of PDA@DCA-COOH membrane were evaluated with methylene blue (MB) and Congo red (CR) as the ionic representatives for their removal. The results indicated that carboxyl, hydroxyl and amine multifunctional groups had been successfully grafted on the surface of the nanofibers with the maximum adsorption capacities of 69.89 and 67.31 mg g −1 for MB and CR, respectively, in the individual systems. The effect of co-existed dyes, inorganic salts and surfactants on the uptake of MB and CR in the simulated real complex system was strongly depended on the initial pH and ionic strength of the solution. The excellent adsorption capacities of the composite membrane were due to strong electrostatic attraction through the abundant functional groups on PDA@DCA-COOH surface. Based on its excellent recycling performance and adsorption property, PDA@DCA-COOH has a promising potential as an effective adsorbent in water treatment.

Stable and Biocompatible Cellulose-Based CaCO3 Microspheres for Tunable pH-Responsive Drug Delivery

Guihua Yan,Yunchao Feng,Zhebang Gao,Xianhai Zeng,Wenjing Hong,Wenjie Liu,Yong Sun,Xing Tang,Tingzhou Lei,Lu Lin

Controlling the structure, particularly the structure template stability, has great potential for the fabrication of high-capacity and renewable drug carriers. Herein, novel porous CaCO3 microspheres about 2–3.5 μm with hollow cellulose nanoparticles (NPs, diameter centered at 15–35 nm) as templates were first assembled, with a highly specific surface area of ∼363 m2/g. The hollow cellulose NPs were previously prepared by the water-soluble dialdehyde cellulose, followed by the reduction of l-arginine (RDACws). Such self-assembled CaCO3 microspheres showed outstanding stability, which could retain high porosity for over 4 weeks under ethanol storage conditions, due to the electrostatic interactions between Ca2+ and the preassembled RDACws nanostructures. Furthermore, the porous CaCO3 microspheres as potential drug carriers showed good encapsulation efficiency, excellent pH responsiveness (pH = 2.0 ≫ 7.4), and good biocompatibility, which could control the drug release at a specific location. The CaCO3 microspheres regulated by sustainable hollow cellulose NPs put forward for the first time a sustained drug release, demonstrating that the cellulose hollow NPs together with the mineralization theory bring a brilliant prospect to biomineral materials.

Preparation, characterization and long-term antibacterial activity of nisin anchored magnetic cellulose beads

Wu Hao,Tian HuaFeng,Li ShuJing,Wang YuTang,Ma ZhaoCheng,Song ZiHan,Wang JianGuo

Along with the concerns for food safety and environment, the demand of cost-effective and biodegradable materials in food treatment is increasing. In order to solve the problem of certain spoilage microorganisms, nisin anchored cellulose beads were prepared by a sol–gel transition method. By mixing γ -Fe 2 O 3 nanoparticles with cellulose in 8% LiOH·H 2 O/15% urea aqueous solution precooled at − 20 °C, regenerated cellulose beads mixed with γ -Fe 2 O 3 nanoparticles (RC) were fabricated via a dropping technology. Subsequently, cellulose beads were oxidized by sodium periodate in dark room and nisin was anchored on the beads (NCs) through Schiff base reaction. The oxidization process and grafting reaction between the amino groups of nisin and the aldehyde groups of oxidized cellulose were confirmed via Fourier transform infrared spectra, field emission scanning electron microscope, energy dispersive X-ray spectroscopy and X-ray diffraction. The beads containing γ -Fe 2 O 3 nanoparticles exhibits the sensitive magnetic response and excellent thermal stability with decomposition temperature over 200 °C. A long-term antimicrobial activity against Alicyclobacillus acidoterrestris DSM 3922 were investigated. To the best of our knowledge, this is the first report of such nisin-anchored beads. The biodegradable nisin-anchored beads are novel antimicrobial materials with great potential in food industry.

Study on the Preparation of Ionic Liquid Doped Chitosan/Cellulose-Based Electroactive Composites

Fang Wang,Chong Xie,Liying Qian,Beihai He,Junrong Li

Electro-actuated polymer (EAP) can change its shape or volume under the action of an external electric field and shows similar behavioral characteristics with those of biological muscles, and so it has good application prospects in aerospace, bionic robots, and other fields. The properties of cellulose-based electroactive materials are similar to ionic EAP materials, although they have higher Young’s modulus and lower energy consumption. However, cellulose-based electroactive materials have a more obvious deficiency—their actuation performance is often more significantly affected by ambient humidity due to the hygroscopicity caused by the strong hydrophilic structure of cellulose itself. Compared with cellulose, chitosan has good film-forming and water retention properties, and its compatibility with cellulose is very excellent. In this study, a chitosan/cellulose composite film doped with ionic liquid, 1-ethyl-3-methylimidazolium acetate ([EMIM]Ac), was prepared by co-dissolution and regeneration process using [EMIM]Ac as the solvent. After that, a conductive polymer, poly(3,4-ethylenedioxythiophene)/poly (styrene sulfonate) (PEDOT: PSS), was deposited on the surface of the resulted composite, and then a kind of cellulose-based electroactive composites were obtained. The results showed that the end bending deformation amplitude of the resulted material was increased by 2.3 times higher than that of the pure cellulose film under the same conditions, and the maximum deformation amplitude reached 7.3 mm. The tensile strength of the chitosan/cellulose composite film was 53.68% higher than that of the cellulose film, and the Young’s modulus was increased by 72.52%. Furthermore, in comparison with the pure cellulose film, the water retention of the composite film increased and the water absorption rate decreased obviously, which meant that the resistance of the material to changes in environmental humidity was greatly improved.Keywords:electroactive materials;electroactive properties;chitosan/cellulose composite film;[EMIM] Ac;mechanical properties

Highly efficient and selective recovery of gallium achieved on an amide-functionalized cellulose

Wanghuan Guo,Jinbo Zhang,Fan Yang,Fengzhi Tan,Zhigang Zhao

Preparation and characterization of carboxymethyl cellulose containing quaternized chitosan for potential drug carrier

Fang Wang,Qian Zhang,Kexin Huang,Jiarui Li,Kun Wang,Kai Zhang,Xinyue Tang

The objective of this study was to synthesize and characterize cystamine dihydrochloride (CYS) crosslinked carboxymethyl cellulose/quaternized chitosan (CMC/HACC) composite hydrogel film. Firstly, the glycidyl-based quaternary ammonium chitosan derivative (HACC) was synthesized using nucleophilic substitution reaction. Then HACC was analyzed by FTIR, 1 HNMR spectra and the composite films at different blending ratio of CMC and HACC were studied by rheology measurement, mechanical and swelling tests. When the composite films were prepared under optimized conditions (CMC: HACC = 7:1), they showed excellent mechanical properties (with improved 93.3% tensile strength and 2.3% elongation at break) and swellability (equilibrium swelling ratio increased 270%) compared to pure CMC film. 5-Fluorouracil (5-FU) was used as drug model which has broad-spectrum anticancer properties. The 5-FU/CMC/HACC composite films showed redox and pH responsive of drug release properties along with well biocompatibility. The in vitro cytotoxicity and cell apoptosis studies showed the drug loaded composite films with obvious toxicity against HepG2 cells especially in the presence of GSH. In addition, CMC/HACC composite films showed good antibacterial against S. aureus and E. coli , while pure CMC film had no antimicrobial activities. It can be concluded that CMC/HACC composite films can be potentially used as targeted drug delivery system.

Injectable antibacterial cellulose nanofiber/chitosan aerogel with rapid shape recovery for noncompressible hemorrhage

Xialian Fan,Yijin Li,Xiumin Li,Yonghui Wu,Keyong Tang,Jie Liu,Xuejing Zheng,Guangming Wan

Here an injectable antibacterial aerogel was fabricated with oxidized cellulose nanofiber and chitosan for rapid hemostasis of noncompressible hemorrhage application. Especially, cellulose nanofiber was modified with carboxyl groups by pre-oxidizing in 2,2,6,6-tetramethylpiperidine-1-oxyl combined with high pressure homogenization. Whereafter, the realized carboxyl group of cellulose nanofiber was reacted with the amidogen of chitosan to yield a strong composite aerogel with a nanofiber/nanosheet interlaced structure, which increased the compressive mechanical strength up to 75.4 kPa. In addition, the nanocellulose/chitosan composite aerogel exhibits high water absorption capacity, rapid shape recovery and good antibacterial ability (via Escherichia coli and Staphylococcus aureus ). Once absorbing water, the nanocellulose5/chitosan5 compressed aerogel could rapidly recover its shape within 30 s. The in vitro coagulation ability measurement showed that the composite aerogel has a good adhesion and aggregation effect to red blood cells and platelets. Hemolysis and cytotoxicity analysis results indicated a good biocompatibility for the composite aerogel.