Hydrophobicity and resistance against microorganisms of heat and chemically crosslinked poly(vinyl alcohol) nanofibrous membranes

ACS Appl. Mater. Interfaces

Wang

et al. 2021

Cellulose nanocrystals (CNCs) are powerful photonic building blocks for the fabrication of biosourced colored films. A combination of the advantages of self-assembled CNCs and multiple templating agents offers access to the development of novel physicochemical sensors, structural coatings, and optic devices. However, due to the inherent brittleness and water instability of CNCderived materials, their further applications are widely questionable and restrictive. Here, a soft polymer of poly(vinyl alcohol) (PVA) was introduced into the rigid CNC system to balance molecular interactions, whereafter two hard/soft nanocomposites were fastened through a cross-linking reaction of glutaraldehyde (GA), resulting in a highly flexible, water-stable, and chiral nematic CNC composite film through an evaporation-induced self-assembly technique. For a 1.5 wt % GA-cross-linked 70 wt % CNC loading film, its treatment with harsh hydrophilic exposure (soaking in a strong acid, strong base, and seawater) and various organic solvents show exceptional solvent-resistant abilities. Furthermore, the film can even withstand a weight of 167 g cm −2 without failure, which is a highly stiff and durable character. Importantly, the film remains a highly ordered chiral nematic organization, being able to act as a highly transparent substrate for selective reflection of left-handed circularly polarized light, preparing fully covered and patterned full-color coatings on various substrates. Our work paves the way for applications in low-cost, durable, and photonic cellulosic coatings.

Section: ■ Results and Discussionmentioning

confidence: 97%

Section: Results and Discussionmentioning

confidence: 97%

Highly Strong and Solvent-Resistant Cellulose Nanocrystal Photonic Films for Optical Coatings

ACS Appl. Mater. Interfaces

Wang

et al. 2021

“…From this point of view, the 0.03% water content of analytical pure toluene can fully hydrolyze OTS and the influence of humidity on the formation of the PODS self-assembled film is negligible. Second, the OTS after hydrolysis is cross-linked by intermolecular polycondensation of –Si-OH groups on neighboring molecules, forming PODS in the later high-coverage stages 31 , 32 . Third, when the hydrolyzed OTS physisorbed on the substrate surface, some PODS molecules organized themselves into crystalline or near crystalline order due to different temperatures, and the formation characteristics of coating depended on the deposition temperature 33 .…”

Section: Resultsmentioning

confidence: 99%

Novel fabrication of hydrophobic/oleophilic human hair fiber for efficient oil/water separation through one-pot dip-coating synthesis route

Yang

Wang

et al. 2022

Sci Rep

Frequent oil spill accidents and industrial wastewater discharge has always been one of the most severe worldwide environmental problems. To cope with this problem, many fluorine-containing and high-cost materials with superwettability have been extensively applied for oil–water separation, which hinders its large-scale application. In this work, a novel human hair fiber (HHF)-polymerized octadecylsiloxane (PODS) fiber was fabricated with a facile one-pot dip-coating synthesis approach, inspired by the self-assembly performance and hydrophobicity of OTS modification. The benefits of prominent hydrophobic/lipophilic behavior lie in the low surface energy, and a rough PODS coating was rationally adhered on the surface of HHF. Driven solely by gravity and capillary force, the HHF-PODS showed excellent oil/water separation efficiency (> 99.0%) for a wide range of heavy and light oil/water mixtures. In addition, HHF-PODS demonstrated durability toward different harsh environments like alkaline, acid, and salty solutions.

“…To improve the mechanical strength of the PVA/HNTs and reduce its swelling degree in electrolyte, we further used glutaraldehyde as a cross-linking agent to react with PVA. 41 To distinguish these membranes, we abbreviated the cross-linked PVA/HNT composite membrane as EPH and the cross-linked electrostatic spinning PVA as EP. Compared to the Celgard separator and the EP separator, the EPH separator shows a higher electrolyte uptake rate, higher Li + conductivity, and excellent mechanical stability, as well as good thermostability and electrochemical stability.…”

Section: Introductionmentioning

confidence: 99%

Cross-Linked PVA/HNT Composite Separator Enables Stable Lithium-Organic Batteries under Elevated Temperature

Gong

Zheng

ACS Appl. Mater. Interfaces

et al. 2022

Li-organic batteries (LOBs) are promising advanced battery systems because of their unique advantages in capacity, cost, and sustainability. However, the shuttling effect of soluble organic redox intermediates and the intrinsic dissolution of smallmolecular electrodes have hindered the practical application of these cells, especially under high operating temperatures. Herein, a cross-linked membrane with abundant negative charge for hightemperature LOBs is prepared via electrospinning of poly(vinyl alcohol) containing halloysite nanotubes (HNTs). The translocation of negatively charged organic intermediates can be suppressed by the electronic repulsion and the cross-linked network while the positively charged Li + are maintained, which is attributed to the intrinsic electronegativity of HNTs and their well-organized and homogeneous distribution in the PVA matrix. A battery using a PVA/HNT composite separator (EPH-10) and an anthraquinone (AQ) cathode exhibits a high initial discharge capacity of 231.6 mAh g −1 and an excellent cycling performance (91.4% capacity retention, 300 cycles) at 25 °C. Even at high temperatures (60 and 80 °C), its capacity retention is more than 89.2 and 80.4% after 100 cycles, respectively. Our approach demonstrates the potential of the EPH-10 composite membrane as a separator for high-temperature LOB applications.