科创中国

Directional water transport is a predominant part of functional textiles used for continuous sweat release in daily life. However, it has remained a great challenge to design such textiles which ensure continuous directional water transport and superior prevention of water penetration in the reverse direction. Here, a scalable strategy is reported to create trilayered fibrous membranes with progressive wettability by introducing a transfer layer, which can guide the directional water transport continuously and spontaneously, thus preventing the skin from being rewetted. The resulting trilayered fibrous membranes exhibit a high one-way transport index R (1021%) and a desired breakthrough pressure (16.1 cm H₂O) in the reverse direction, indicating an ultrahigh directional water transport capacity. Moreover, on the basis of water transport behavior, a plausible mechanism is proposed to provide insight into the integrative and cooperative driving forces at the interfaces of trilayered hydrophobic/transfer/superhydrophilic fibrous membranes. The successful synthesis of such fascinating materials would be valuable for the design of functional textiles with directional water transport properties for personal drying applications.

Dongyang Miao;Zhan Huang;Xianfeng Wang;建勇 俞;彬 丁

Small

2018-8-9

A conceptually new, metal-free electrocatalyst, black phosphorus (BP) is presented, which is further downsized to quantum dots (QDs) for larger surface areas, and thus, more active sites than the bulk form. However, BP QDs are prone to agglomeration, which inevitably results in the loss of active sites. Besides, their poor conductivity is not favorable for charge transport during electrolysis. To solve these problems, an electrochemically active, electrically conductive matrix, black tin oxide (SnO_2−x) nanotubes, is employed for the first time. Through facile self-assembly, BP QDs are stably confined on the SnO_2−x nanotubes due to Sn-P coordination, resulting in a robust, double-active electrocatalyst. Benefiting from their synergistic superiority, the BP@SnO_2−x nanotubes deliver impressively high ammonia yield and Faradaic efficiency, which represent a successful attempt toward advanced hybrid electrocatalysts for ambient nitrogen fixation.

Yi Tao Liu;Di Li;建勇 俞;彬 丁

Angewandte Chemie - International Edition

2019-11-11

Tapered 3D braided composites are prepared by column yarn-reduction technique, unit yarn-reduction technique and cutting, respectively. Bending properties in the tapered regions of the composites are obtained by three-point bending tests, and SEM photographs of the fracture surfaces are observed to analyze the failure mechanisms. Results show that bending modulus and bending strength of the yarn-reduction composites are significantly higher than those of the cut composites, and the unit yarn-reduction composites are slightly stronger than the column yarn-reduction composites. The saw-tooth propagation of matrix crackings and interfacial debondings are the primary failure mechanisms of the yarn-reduction composites, while yarn breakages and yarn pulling-outs are the main failure modes of the cut composites.

Cancan Cheng;Zhaolin Liu;Lifang Liu;建勇 俞

2011

As a fundamental step towards creating a new class of cellulose engineering materials, the proposed research investigated swelling and dissolution of cellulose in NaOH aqueous solvent systems (NaOH/H₂O, NaOH/thiourea/H₂O and NaOH/thiourea/urea/H₂O). The dependence of swelling and dissolution behavior of cellulose fibers on the quality of the solvent was investigated in detail. For the two cellulose samples - cotton linter and spruce wood fibers - the swelling and dissolution mechanisms in NaOH-water and NaOH-water-additives stayed the same. Adding thiourea to NaOH-water produced the same ballooning mechanism, but with a larger expansion of the balloons, indicating a better solvent. The cotton fiber could not completely dissolve in NaOH/H₂O and NaOH/thiourea/H₂O. However, the cotton fiber swelled evidently showing no balloon formation and then disintegrated into rod-like fragments in NaOH/thiourea/urea/H₂O, which was an indication of the best solvent of all the NaOH aqueous solutions used.

Shuai Zhang;Wen Cong Wang;Fa Xue Li;建勇 俞

Cellulose Chemistry and Technology

2013-11

In the global transition to a sustainable low-carbon economy, CO₂ capture and storage technology plays a key role in reducing emissions. Metal-organic frameworks (MOFs) are crystalline materials with ultrahigh porosity, tunable pore size, and rich functionalities, holding the promise for CO₂ capture. However, the intrinsic fragility and depressed processability of MOF crystals make the fabrication of the flexible MOF nanofibrous membrane (NFM) rather challenging. Herein, we demonstrate an effective strategy for the versatile preparation of self-supported and flexible HKUST-1 NFM with ultrahigh HKUST-1 loading (up to 82 wt %) and stable and uniform HKUST-1 growth through the combination of electrospinning, multistep seeded growth, and activation process. The loading rate of MOF is the highest level among the reported analogues. Significantly, the HKUST-1 NFM exhibits a prominent CO₂ adsorption capacity of 3.9 mmol g^-1, good CO₂/N₂ selectivity, and remarkable recyclability. The CO₂ capacity retains ∼95% (3.7 mmol g^-1) of the initial value after 100 adsorption-desorption cycles, indicating that the HKUST-1 NFM has long-term and ultrastable recyclability and a significant practical value. Thus, the low-cost and scalable production pathway is able to convert MOF particles into self-supported and flexible NFMs, and thereby, they are better applied to the efficient postcombustion CO₂ capture.

Yuge Zhang;Yufei Zhang;Xianfeng Wang;建勇 俞;彬 丁

ACS applied materials & interfaces

2018-10-10

Mechanisms of unit yarn-reduction braiding were investigated and preform microstructures were characterized by digital image photography and topological analysis. Flexural properties and failure mechanisms of the unit yarn-reduction composites, cut composites and uniform composites were compared. Results indicated that continuity of the braiding process must be ensured after yarn reduction and distribution of the reduction units should be uniform. A smoothly trapezoidal profile appeared near the unit yarn-reduction cross-section and braiding angles and yarn lengths in the surface or interior yarn-reduction control volumes all increased. Flexural properties of the unit yarn-reduction composites were significantly higher than those of the cut composites and slightly lower than the uniform composites. The damage process of the yarn-reduction composites can be divided into the initial, developing and serious damage stages with yarn breakage being the dominant failure mechanism, while the primary failure mechanisms of the cut composites were matrix microcracking and fiber pulling-out.

Zhaolin Liu;Lifang Liu;建勇 俞

Composites - Part A: Applied Science and Manufacturing

2011-12

A novel superhydrophilic and underwater superoleophobic nanofibrous membrane with a hierarchical structured skin for the separation of oil-in-water emulsions was prepared via electrospinning and electrospraying methods, and was found to exhibit excellent separation efficiency, robust antifouling properties, and extremely high flux solely driven by gravity.

Jianlong Ge;Jichao Zhang;Fei Wang;Zhaoling Li;建勇 俞;彬 丁

Journal of Materials Chemistry A

2017

Spider-spun fiber is of extraordinary strength and toughness comparable to those of electrospun fiber, the later needs a very high voltage (from several thousands voltage to several ten thousands voltages) applied to water-soluble protein "soup" that was produced by a spider, furthermore, its mechanical strength dramatically decreases comparable to spider silk. A possible mechanism in spider-spinning process is given, the distinct character in spider-spinning is that its spinneret consists of millions of nano scale tubes, and a bubble can be produced at the apex of each nano-tube. The surface tension of each bubble is extremely small such that it can be spun into nanofibers with an awfully small force, either by the spider's body weight or tension created by the rear legs. We mimic the spider-spinning in electrospinning using an aerated solution, which leads to various small bubbles on surface with very small surface tension, as a result the bubble can be easily electrospun into nanofibers with low applied voltage. This fabrication process possesses features of high productivity, versatility, in addition, the minimum diameter of nanofibers produced by this process can reach as small as 50 nm.

Ji Huan He;Yong Liu;岚 徐;建勇 俞;Gang Sun

Chaos, Solitons and Fractals

2008-8

Functional semiconductor nanomaterials modified TiO₂ fibrous membranes with desirable heterostructures, good mechanical properties, and superior visible-light-driven photocatalytic activity would have broad applications in environmental remediation; however, constructing such fantastic fibrous membranes still remains an enormous challenge. Herein, we fabricated a soft and heterostructured g-C₃N₄@Co-TiO₂ (CNCT) nanofibrous membranes by a facile electrospinning approach and subsequent thermal polymerization process. The ultrathin g-C₃N₄ nanoshell was in situ synthesized and uniformly wrapped onto Co-TiO₂ nanofiber to form core-shell quantum heterojunction, and the thickness and loading amount of g-C₃N₄ nanoshell can be precisely controlled through simply regulating the content of precursor (melamine). Benefiting from the three-dimensional porous networks, enhanced visible-light response, and the effective charge transfer induced by uniform and compact heterojunction, the as-synthesized CNCT membranes exhibited a prominent photodegradation efficiency of 90.8% within 60 min towards tetracycline hydrochloride, and also displayed excellent antibacterial performance with a 6 log inactivation of E. coil after 90 min visible light exposure. Moreover, the stable core-shell structures and robust mechanical strength also endow the membranes with favorable reversibility and easy-recycling ability. This study may open up new avenues for designing and constructing flexible high-performance photocatalytic membranes for water purification.

Jun Song;Xiaohui Wu;Meng Zhang;C. Liu;建勇 俞;Gang Sun;Yang Si;彬 丁

Chemical Engineering Journal

2020-1-1

Metal organic-frameworks (MOFs) with intriguing structural motifs and unique properties are potential candidates for carbon dioxide (CO₂) storage. Although structures with the single functional constructions and micropores were demonstrated to capture CO₂ with high capacities at low temperature, their feeble interactions still limit practical applications at room temperature. Herein, we report in situ growth observation of hierarchical pores in copper(ii) benzene-1,3,5-tricarboxylate (Cu-BTC) doped MOFs which gives high adsorption and enhances the CO₂ binding ability. Thus, understanding this CO₂-capturing mechanism, which has been causing controversy, is crucial for further development toward advanced study. The doped MOFs exhibit high specific surface areas of 1180 m² g^-1 and show good capacity to store CO₂, which is mainly due to the presence of acid and amine functionalized CNTs and a large amount of narrow micropores (<1.0 nm).

Nousheen Iqbal;Xianfeng Wang;建勇 俞;Naila Jabeen;Hameed Ullah;彬 丁

RSC Advances

2016