In this work, a self-hardening foam-sol (SHF) is proposed to control the diffusion of static coal dust. The SHF was mainly synthesized by a foaming solution (composed of 1 g/L polyethylene oxide (PEO), 25 g/L sodium dodecyl sulfate (SDS), 100 g/L sodium silicate and 874 g/L water) and organic acid with a concentration range of 10 to 13 g/L. Based on fluorescence spectrophotometry , drop shape analysis, X-ray photoelectron spectroscopy and scanning electron microscopy, several conclusions could be found. The critical micelle concentration of SDS was 25 g/L, when most of the pyrene pendants were solubilized into the SDS micelles to form the hydrophobic mixed micelles, and excimer formation began to reach a maximum. The SHF had optimal wetting ability with the smallest contact angle of 17 o , due to PEO-bonded water and SDS forming hydrogen and a dual adsorption layer, which could enhance the wetting ability of the SHF on coal dust surfaces. The SHF had the best accepted loss of liquidity time (180–86 s) and self-hardening time (236–121 s) via the reaction of sodium silicate and organic acid. The pores and cracks among dust particles could be linked closely by SHF via the solid bridge force. The primary components were silica and sodium carbonate with crystal water and hydrophilic C O and C O or O–C–O functional groups. Based on the dust suppression experiment, the dust suppression efficiency was almost 100% at airflow speeds below 12 m/s. Obviously, the dust particles could be controlled via their surfaces being covered by a layer of SHF, since the SHF has strong hydrophilic properties and the solid bridge force. In addition, vehicle-mounted SHF preparation equipment was designed.
Gaoqi Wang,Ding Weng,Chaolang Chen,Lei Chen,Jiadao Wang
The aim of the study was to explore the synergistic effects of nanostructure size and surface treatment of TiO 2 coatings on its wettability and bacteria adhesion. The coatings were fabricated by TiO 2 particles with a diameter ranging from 25 nm to 300 nm. The surface wettability of coatings was tuned by chemical treatment. The anti-adhesion property of as-prepared coatings was evaluated with Streptococcus mutans in two types of solutions: phosphate buffer solution (PBS) and PBS with 1 wt% sucrose. The results show that particle size and surface treatment have significant influences on the wettability (with contact angles of 0–160°) and bacterial adhesion. The coating prepared by chemically modified 25 nm particles has a superhydrophobic property, and could inhibit bacterial adhesion in aqueous solutions with sucrose or not. The study also provides a facile, universal and low-cost process to fabricate anti-adhesion coating, which is applicable for diverse of substrates.
Ming Li,Xiaohong Liu,Ning Liu,Zihe Guo,Puneet Kumar Singh,Shiyu Fu
Cellulose nanocrystals (CNCs) is a kind of natural, renewable, and biocompatible materials that can be functional via the surface modification. A covalently bonded CNCs-g-PDMAEMA was prepared by grafting 2-(dimethyl-amino) ethyl methacrylate (DMAEMA) on the CNCs’ surface via atom transfer radical polymerization (ATRP). Subsequently, the tertiary amino groups of the CNCs-g-PDMAEMA were transferred to quaternary ammonium groups by adding alkyl bromides with different carbon chain lengths (C10-C18). It was found that the antibacterial activity of the prepared materials is related to the quaternary group structure. The material containing C10 alkyl in quaternary group exhibited the best antibacterial efficiency, which was closely associated with the wettability of the quaternary CNCs-based polymers. The lower wettability of materials with higher hydrophobicity may impose a restriction on the polymeric antibacterial groups’ accessibility to the cytoplasmic membrane of bacteria. The antimicrobial CNCs-based composites may be potential to apply as coating agents for aseptic packaging.
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