Nan Zhang

Bio: Nan Zhang is an academic researcher from Jiangnan University. The author has contributed to research in topics: Wool & Surface modification. The author has an hindex of 5, co-authored 14 publications receiving 114 citations.

Eco-friendly Grafting of Chitosan as a Biopolymer onto Wool Fabrics Using Horseradish Peroxidase

Abstract: Chitosan and enzymes have been extensively used in modification of wool, due to their non-toxic and eco-friendly characteristics, as well as to reduce pollution in textile production. In the present work, chitosan was grafted onto wool fabrics using horseradish peroxidase (HRP) in order to endow wool with outstanding properties. The reaction mechanism, grafting percentage, and properties of chitosan-grafted pretreated wool fabric including wettability, dyeability, shrink resistance, and antibacterial activity were studied. P-hydroxyphenylacetamide (PHAD), as a model compound for tyrosine residues in wool, was used to study the mechanism of HRP-mediated grafting of chitosan onto wool. UV and FTIR analyses indicated that quinones, which are intermediate of HRP/H2O2-catalyzed PHAD, reacted with the amino groups of chitosan by Schiff base or Michael addition reactions. Scanning electron microscopy (SEM) showed that dichloroisocyanuric acid pretreatment had an etching effect and some substances were deposited onto the wool fiber. SEM and Fourier transform infrared (FTIR) spectroscopy further confirmed the covalent grafting of chitosan onto wool. Compared with chitosan-grafted unpretreated wool, there was an obvious improvement in grafting efficiency of chitosan onto wool fabric, physical and mechanical properties after pretreatment and chitosan grafting on the wool. For chitosan-grafted pretreated wool fabrics, there was no observable change in the thermal behavior, while the hydrophilicity, dyeability, shrinkage resistance, and antibacterial activity were remarkably improved compared to that of untreated wool. The present work offers a new ecologically acceptable process of grafting chitosan on the wool.

A novel “trifunctional protease” with reducibility, hydrolysis, and localization used for wool anti-felting treatment

Abstract: Proteases can cause unacceptable fiber damage when they are singly applied to wool anti-felting treatment which can make wool textiles machine-washable. Even if protease is attached by synthetic polymers, the modified protease plays a limited role in the degradation of keratin with dense structure consisting of disulfide bonds in the scales. Here, to obtain "machine-washable" wool textiles, a novel "trifunctional protease" with reducibility, hydrolysis, and localization is developed by means of covalent bonding of protease molecules with poly (ethylene glycol) bis (carboxymethyl) ether (HOOC-PEG-COOH) and L-cysteine using carbodiimide/N-hydroxysuccinimide (EDC/NHS) coupling, aiming at selectively degrading the scales on the surface of wool. The formation of polymer is confirmed with size exclusion chromatography (SEC) and Fourier transform infrared spectroscopy (FT-IR). Ellman's test and fluorescence microscopy reveal that the modified protease can reduce disulfide bonds and restrict hydrolysis of peptide bonds on the wool scales. Furthermore, when applied to wool fabrics, the modified protease reach better treatment effects considering dimensional stability to felting (6.12%), strength loss (11.7%) and scale dislodgement proved by scanning electron microscopy (SEM), alkali solubility, wettability, and dyeability. This multifunctional enzyme is well-designed according to the requirement of the modification of wool surface, showing great potential for eco-friendly functionalization of keratin fibers rich in disulfide linkage.

Functionalized Fiber-Based Strain Sensors: Pathway to Next-Generation Wearable Electronics

Abstract: Wearable strain sensors are arousing increasing research interests in recent years on account of their potentials in motion detection, personal and public healthcare, future entertainment, man-machine interaction, artificial intelligence, and so forth. Much research has focused on fiber-based sensors due to the appealing performance of fibers, including processing flexibility, wearing comfortability, outstanding lifetime and serviceability, low-cost and large-scale capacity. Herein, we review the latest advances in functionalization and device fabrication of fiber materials toward applications in fiber-based wearable strain sensors. We describe the approaches for preparing conductive fibers such as spinning, surface modification, and structural transformation. We also introduce the fabrication and sensing mechanisms of state-of-the-art sensors and analyze their merits and demerits. The applications toward motion detection, healthcare, man-machine interaction, future entertainment, and multifunctional sensing are summarized with typical examples. We finally critically analyze tough challenges and future remarks of fiber-based strain sensors, aiming to implement them in real applications.

Functionalized Fiber-Based Strain Sensors: Pathway to Next-Generation Wearable Electronics

Abstract: Wearable strain sensors are arousing increasing research interests in recent years on account of their potentials in motion detection, personal and public healthcare, future entertainment, man-machine interaction, artificial intelligence, and so forth. Much research has focused on fiber-based sensors due to the appealing performance of fibers, including processing flexibility, wearing comfortability, outstanding lifetime and serviceability, low-cost and large-scale capacity. Herein, we review the latest advances in functionalization and device fabrication of fiber materials toward applications in fiber-based wearable strain sensors. We describe the approaches for preparing conductive fibers such as spinning, surface modification, and structural transformation. We also introduce the fabrication and sensing mechanisms of state-of-the-art sensors and analyze their merits and demerits. The applications toward motion detection, healthcare, man-machine interaction, future entertainment, and multifunctional sensing are summarized with typical examples. We finally critically analyze tough challenges and future remarks of fiber-based strain sensors, aiming to implement them in real applications.