High Efficiency of Formaldehyde Removal and Anti-bacterial Capability Realized by a Multi-Scale Micro–Nano Channel Structure in Hybrid Hydrogel Coating Cross-Linked on Microfiber-Based Polyurethane

Abstract

Inspired by the transpiration in the tree stem having a vertical and porous channel structure, high efficiency of formaldehyde removal is realized by the multi-scale micro–nano channel structure in a hybrid P­(AAm/DA)-Ag/MgO hydrogel coating cross-linked on microfiber-based polyurethane. The present multi-scale channel structure is formed by a joint effect of directional freezing and redox polymerization as well as nanoparticles-induced porosity. Due to the large number of vertically aligned channels of micrometer size and an embedded porous structure of nanometer size, the specific surface area is significantly increased. Therefore, formaldehyde from solution can be rapidly adsorbed by the amine group in the hydrogels and efficiently degraded by the Ag/MgO nanoparticles. By only immersing in formaldehyde solution (0.2 mg mL–1) for 12 h, 83.8% formaldehyde is removed by the hybrid hydrogels with a multi-scale channel structure, which is 60.8% faster than that observed in hydrogels without any channel structure. After cross-linking the hybrid hydrogels with a multi-scale channel structure to microfiber-based polyurethane and exposing to the formaldehyde vapor atmosphere, 79.2% formaldehyde is removed in 12 h, which is again 11.2% higher than that observed in hydrogels without any channel structure. Unlike the traditional approaches to remove formaldehyde by the light catalyst, no external conditions are required in our present hybrid hydrogel coating, which is very suitable for indoor use. In addition, due to the formation of free radicals by the Ag/MgO nanoparticles, the cross-linked hybrid hydrogel coating on polyurethane synthetic leather also shows good anti-bacterial capability. 99.99% of Staphylococcus aureus can be killed on the surface. Based on the good ability to remove formaldehyde and to kill bacteria, the obtained microfiber-based polyurethane cross-linked with a hybrid hydrogel coating containing a multi-scale channel structure can be used in a broad field of applications, such as furniture and car interior parts, to simultaneously solve the indoor air pollution and hygiene problems.

MoO3 Nanorods Coated with MoS2 Nanosheets for Photocatalytic Elimination of Bacteria and Formaldehyde

“…As shown in Figure S11, SEM images before and after the degradation of formaldehyde by the coating were observed and compared, and the overall structure of the coating did not change significantly, indicating that light irradiation did not have a significant effect on the coating (Table S1). Summarizes a number of reports of coatings eliminating formaldehyde, further demonstrating the superior performance of the coating in eliminating formaldehyde. − The formaldehyde degradation experiment was carried out with 0.1 g of pure photocatalyst, and it could be seen from Figure S12 that it has about 85% of the elimination effect, which indicated that the formaldehyde elimination efficiency was improved after preparation into the coating. To summarize, the coatings were effective for the elimination of formaldehyde…”

Anisotropically Conductive Hydrogels with Directionally Aligned PEDOT:PSS in a PVA Matrix

“…In our sequential fabrication process, we achieved a directionally aligned microstructure with pores between layers that varied over 1 order of magnitude from 1 to 10 μm; these variations affected the alignment and layering of the architecture (Figure M). Moreover, the surface of the final product was assessed through SEM-EDS mapping, − which showed that PEDOT:PSS was uniformly coated on the PVA matrix (Figure S2, Supporting Information). To compare the effects of directional versus non-directional freezing on the microstructure, we used non-directional freezing in place of the directional freezing-induced alignment process (Figure G).…”

Biocompatible Thermally Responsive Vinyl Sulfone Silica Nanocapsules as Stabilizing and Softening Agents for Metal-Free Leather Production

“…Additionally, the increase in the intensity of broad band at 3298 cm –1 shows the intermolecular hydrogen bonding between the –OH groups of silica and castor oil, which proves the encapsulation of oil in silica nanocapsules. Furthermore, to improve the clarity on encapsulation of castor oil in silica nanocapsules, EDAX elemental composition ,,, was carried out for bare silica nanocapsules with vinyl sulfone terminal and oil-loaded silica nanocapsules with a vinyl sulfone terminal. The EDAX elemental composition for silica with vinyl sulfone terminal with and without oil is displayed in Table S2.…”