Facile Fabrication of Superhydrophobic Paper with Excellent Water Repellency and Moisture Resistance by Phase Separation

Abstract

A simple but effective method of fabricating superhydrophobic paper with excellent moisture resistance was developed by precipitating carnauba wax onto the surface of cellulose fibers using a phase separation method. Response surface methodology (RSM) was used to optimize the effects of the preparation variables on the water contact angle (WCA) of the paper surface. The four independent variables were carnauba wax concentration, immersion time, coagulation bath ratio (water/ethanol), and coagulation bath time. The optimal treatment conditions were as follows: wax concentration, 3.78% (wax/chloroform, w/v); immersion time, 1.46 h; coagulation bath ratio, 13/87 (water/ethanol, v/v); and coagulation bath time, 2.63 h. Under these conditions, the experimental WCA reached 152.7°, which agreed closely with the predicted value of 154.1°. The surface morphology of the superhydrophobic paper was characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM), and the images showed that cluster-like carnauba wax aggregation completely covered the fiber surface, resulting in increased roughness. Moreover, the moisture resistance of the obtained superhydrophobic paper was evaluated. The results demonstrated that under high relative humidity conditions, the moisture resistance of the superhydrophobic paper significantly improved, and its tensile strength remained high.

Rational design of materials interface at nanoscale towards intelligent oil–water separation

“…Beyond the modification methods mentioned above, other methods such as layer by layer assembling, candle-soot coating, incorporation, phase separation and gas phase coating strategies have also been developed to achieve special wettability. [190][191][192][193][194] Layer-by-layer assembling approach, usually with electrostatic interactions between each layer, can provide the flexibility to improve adhesion to the substrate and create a low surface tension coating at the air interface. [195] For example, Lin et al created a superhydrophobic surface firstly via a versatile electrostatic layer by layer self-assembly technique for constructing micro/nano surface structures, followed by a post-fluorinating modification.…”

Surface Energy and Lewis Acid-base Characteristics of Lignocellulosic Fibers upon Modification by Chemical Vapor Deposition of Trichloromethylsilane: An Inverse Gas Chromatography Study

“…[3,7] Furthermore, those methods usually are either timeconsuming intricate strategies or they focus almost exclusively on high-purity cellulosic fibers, in which the negative effect of the presence of the other wood components on the efficiency of these modification strategies is obviated. For instance, superhydrophobic paper was obtained by physical precipitation of carnauba wax onto the surface of cellulose fibers, upon immersion of filter paper in a chloroform solution containing the wax for 2 h and further coagulation in a water/ethanol bath for 3 h. [8] On the other hand, superhydrophobic peroxide-bleached thermomechanical pulp (TMP) paper was also obtained by combining O 2 etching and plasma-enhanced chemical vapor deposition of fluorocarbon, [9] rendering chemically-bonded coatings. Likewise, an example for the superhydrophobization of lignocellulosic fibers is given by the treatment of bamboo surfaces by combining a hydrothermal process with ZnO and chemical vapor deposition (CVD) of fluoroalkyl silane at 130°C for 3 h. [10] Recently, softwood and hardwood surfaces were hydrophobized using a combination of O 2 plasma activation and coating of pre-hydrolyzed methyltrimethoxysilane.…”

The Effect of External and Internal Application of Organosilicon Compounds on the Hydrophobicity of Recycled OCC Paper

“…In addition, other numerous modification methods for improving the hydrophobicity of cellulosic fiber-based paper, such as filling with hydrophobic nanoparticles, wax coating, layer-by-layer, phase separation and enzyme treatment, etc., have been proposed (Huang et al 2011;Cusola et al 2013;Obeso et al 2013;Zhang et al 2014;Li et al 2016;Peng et al 2016). Many studies have attempted to find new formulas with the same performance but with fewer costs, environmental concerns, and process difficulties (Hutton and Parker 2009;Rahmaninia et al 2016).…”