Donghua University

About: Donghua University is a education organization based out in Shanghai, China. It is known for research contribution in the topics: Fiber & Nanofiber. The organization has 21155 authors who have published 21841 publications receiving 393091 citations. The organization is also known as: Dōnghuá Dàxué & China Textile University.

Mechanically and Electronically Robust Transparent Organohydrogel Fibers.

Abstract: Stretchable conductive fibers are key elements for next-generation flexible electronics. Most existing conductive fibers are electron-based, opaque, relatively rigid, and show a significant increase in resistance during stretching. Accordingly, soft, stretchable, and transparent ion-conductive hydrogel fibers have attracted significant attention. However, hydrogel fibers are difficult to manufacture and easy to dry and freeze, which significantly hinders their wide range of applications. Herein, organohydrogel fibers are designed to address these challenges. First, a newly designed hybrid crosslinking strategy continuously wet-spins hydrogel fibers, which are transformed into organohydrogel fibers by simple solvent replacement. The organohydrogel fibers show excellent antifreezing ( 5 months), transparency, and stretchability. The predominantly covalently crosslinked network ensures the fibers have a high dynamic mechanical stability with negligible hysteresis and creep, from which previous conductive fibers usually suffer. Accordingly, strain sensors made from the organohydrogel fibers accurately capture high-frequency (4 Hz) and high-speed (24 cm s-1 ) motion and exhibit little drift for 1000 stretch-release cycles, and are powerful for detecting rapid cyclic motions such as engine valves and are difficult to reach by previously reported conductive fibers. The organohydrogel fibers also demonstrate potential as wearable anisotropic sensors, data gloves, soft electrodes, and optical fibers.

A highly sensitive humidity sensor based on a nanofibrous membrane coated quartz crystal microbalance.

Abstract: A novel humidity sensor was fabricated by electrospinning deposition of nanofibrous polyelectrolyte membranes as sensitive coatings on a quartz crystal microbalance (QCM). The results of sensing experiments indicated that the response of the sensors increased by more than two orders of magnitude with increasing relative humidity (RH) from 6 to 95% at room temperature, exhibiting high sensitivity, and that, in the range of 20-95% RH, the Log(Deltaf) showed good linearity. The sensitivity of fibrous composite polyacrylic acid (PAA)/poly(vinyl alcohol) (PVA) membranes was two times higher than that of the corresponding flat films at 95% RH. Compared with fibrous PAA/PVA membranes, the nanofibrous PAA membranes exhibited remarkably enhanced humidity sensitivity due to their high PAA content and large specific surface area caused by the formation of ultrathin nanowebs among electrospun fibers. Additionally, the resultant sensors exhibited a good reversible behavior and good long term stability.

Facile immobilization of gold nanoparticles into electrospun polyethyleneimine/polyvinyl alcohol nanofibers for catalytic applications

Abstract: We report a facile approach to immobilizing gold nanoparticles (AuNPs) into electrospun polyethyleneimine (PEI)/polyvinyl alcohol (PVA) nanofibers for catalytic applications. In this study, electrospun PEI/PVA nanofibers with a mean diameter of 490 nm were first crosslinked with glutaraldehyde vapor to render them water stable. Then, the water-insoluble nanofibrous mats were used as nanoreactors to complex AuCl4− anions via binding with the free amine groups of PEI for subsequent formation and immobilization of AuNPs. The formed AuNPs with a diameter of 11.8 nm within the nanofibers do not significantly change the morphology of the nanofibers; while importantly the mechanical property of the fibers was greatly improved compared to the crosslinked fibers without AuNPs. Scanning electron microscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, energy dispersive spectroscopy, and thermogravimetric analysis were used to characterize these hybrid nanofibers. Furthermore, we show that the AuNP-containing nanofibers display an excellent catalytic activity and reusability for the transformation of 4-nitrophenol to 4-aminophenol. The present approach to fabricating AuNP-containing nanofibers may be extended for producing other nanoparticle-containing composite nanofibrous materials for various applications in catalysis, sensing, and biomedical sciences.

Mussel-Inspired Multifunctional Hydrogel Coating for Prevention of Infections and Enhanced Osteogenesis.

Abstract: Prevention of postsurgery infection and promotion of biointegration are the key factors to achieve long-term success in orthopedic implants. Localized delivery of antibiotics and bioactive molecules by the implant surface serves as a promising approach toward these goals. However, previously reported methods for surface functionalization of the titanium alloy implants to load bioactive ingredients suffer from time-consuming complex processes and lack of long-term stability. Here, we present the design and characterization of an adhesive, osteoconductive, and antimicrobial hydrogel coating for Ti implants. To form this multifunctional hydrogel, a photo-cross-linkable gelatin-based hydrogel was modified with catechol motifs to enhance adhesion to Ti surfaces and thus promote coating stability. To induce antimicrobial and osteoconductive properties, a short cationic antimicrobial peptide (AMP) and synthetic silicate nanoparticles (SNs) were introduced into the hydrogel formulation. The controlled release of AMP loaded in the hydrogel demonstrated excellent antimicrobial activity to prevent biofilm formation. Moreover, the addition of SNs to the hydrogel formulation enhanced osteogenesis when cultured with human mesenchymal stem cells, suggesting the potential to promote new bone formation in the surrounding tissues. Considering the unique features of our implant hydrogel coating, including high adhesion, antimicrobial capability, and the ability to induce osteogenesis, it is believed that our design provides a useful alternative method for bone implant surface modification and functionalization.