scholarly journals Facile Fabrication of Multi-Hydrogen Bond Self-Assembly Poly(MAAc-co-MAAm) Hydrogel Modified PVDF Ultrafiltration Membrane to Enhance Anti-Fouling Property

Membranes ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 761
Author(s):  
Weigui Fu ◽  
Guoxia Li ◽  
Gaowei Zhai ◽  
Yunji Xie ◽  
Meixiu Sun ◽  
...  
Keyword(s):  
Contact Angle ◽  
Water Contact Angle ◽  
Self Assembly ◽  
Vinylidene Fluoride ◽  
Pure Water ◽  
Polymer Gel ◽  
Hydrophobic Membrane ◽  
Water Contact ◽  
Monomer Ratio ◽  
Gel Layer

In this work, a facile preparation method was proposed to reduce natural organics fouling of hydrophobic membrane via UV grafting polymerization with methacrylic acid (MAAc) and methyl acrylamide (MAAm) as hydrophilic monomers, followed by multihydrogen bond self-assembly. The resulting poly(vinylidene fluoride)-membranes were characterized with respect to monomer ratio, chemical structure and morphology, surface potential, and water contact angle, as well as water flux and organic foulants ultrafiltration property. The results indicated that the optimal membrane modified with a poly(MAAc-co-MAAm) polymer gel layer derived from a 1:1 monomer ratio exhibited superior hydrophilicity and excellent gel layer stability, even after ultrasonic treatment or soaking in acid or alkaline aqueous solution. The initial water contact angle of modified membranes was only 36.6° ± 2.9, and dropped to 0° within 13 s. Moreover, flux recovery rates (FRR) of modified membranes tested by bovine serum albumin (BSA), humic acid (HA), and sodium alginate (SA) solution, respectively, were all above 90% after one-cycle filtration (2 h), significantly higher than that of the pure membrane (70–76%). The total fouling rates (Rt) of the pure membrane for three foulants were as high as 47.8–56.2%, while the Rt values for modified membranes were less than 30.8%. Where Rt of BSA dynamic filtration was merely 10.7%. The membrane designed through grafting a thin-layer hydrophilic hydrogel possessed a robust antifouling property and stability, which offers new insights for applications in pure water treatment or protein purification.

Fast and simple fabrication of SiO2/poly(vinylidene fluoride) coated cotton fabrics with asymmetric wettability via a facile spray-coating route

2018 ◽  
Vol 89 (6) ◽  
pp. 1013-1026 ◽  
Author(s):  
Rongrong Yu ◽  
Mingwei Tian ◽  
Lijun Qu ◽  
Shifeng Zhu ◽  
Jianhua Ran ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Contact Angle ◽  
Water Contact Angle ◽  
Vinylidene Fluoride ◽  
Spray Coating ◽  
Cotton Fabrics ◽  
Water Repellent ◽  
Water Contact ◽  
Repellent Property ◽  
Poly Vinylidene Fluoride

Cotton fabrics with hydrophilic-to-hydrophobic asymmetric surfaces are attractive as potential utilizable structures for functional garments. The spray-coating route could be deemed as a fast and simple way to achieve asymmetric surfaces. In this paper, SiO2 nanoparticles with size ∼ 205 nm were synthesized via the modified sol-gel method, and then modified with poly(vinylidene fluoride) (PVDF) to form a hydrophobic surface. The SiO2 nanoparticles modified with PVDF were uniformly deposited on the outer surface of cotton fabric aided with the robust air flow force from the sprayer. The morphology and chemical structures were characterized by scanning electron microscopy, mapping, atomic force microscopy, X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy. The results indicated that SiO2 nanoparticles were evenly deposited on the surface of cotton fibers and stable interfacial interaction occurred between SiO2 and PVDF molecular chains. The existence of SiO2 could increase the roughness of the fabric surface, which could enhance the water-repellent property of the coated fabrics. Furthermore, the water-repellent property and thermal insulation properties were evaluated via the water contact angle and thermal conductivity tests, respectively, and the results showed that 20 wt.% SiO2/PVDF fabric achieved a desirable level of contact angle, 136.6°, which was the largest water contact angle among all the samples, and the lowest thermal conductivity of 0.033 W/mK, resulting from the existence of SiO2 nanoparticles. Such a fast and simple spray-coating strategy could be widely introduced into asymmetric fabric modification, and such asymmetric fabrics with reasonable water-repellent and thermal insulating outer surfaces could act as candidates in the field of functional garments.

scholarly journals Optimization of Process Parameters for a Chemi-Absorbed Graphene Coating and Its Nano Tribological Investigation

Nanomaterials ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 55 ◽  
Author(s):  
Pengfei Li ◽  
Yuncheng Li ◽  
Hongyue Chen ◽  
Hui Liu ◽  
Xianhua Cheng
Keyword(s):  
Contact Angle ◽  
Graphene Oxide ◽  
Water Contact Angle ◽  
Coefficient Of Friction ◽  
Process Parameters ◽  
Self Assembly ◽  
Titanium Substrate ◽  
Oxide Coating ◽  
Water Contact ◽  
Hydrothermal Temperature

A reduced graphene oxide coating was deposited on a titanium substrate for potential anti-friction applications in nano- or micro-mechanical systems. A γ-aminopropyltriethoxysilane coating was self-assembled on the substrate as an adhesive interlayer beforehand. The process parameters of self-assembly and hydrothermal reduction of graphene oxide coating were explored via water contact angle and tribological tests. Insufficient self-assembly duration of graphene oxide layer can be detected by water contact angle results, and the corresponding coating displayed a higher coefficient of friction and shorter anti-wear lifetime than the optimized one. Proper hydrothermal temperature and duration were also confirmed by its water contact angle, coefficient of friction and anti-wear lifetime. Noticeably, excessive hydrothermal temperature or duration would reduce the coefficient of friction, but diminish the anti-wear resistance. The optimized process parameters were confirmed as assembly duration of graphene oxide coating for 12 h, hydrothermal reduction duration of 6–8 h at 135 °C. Nano tribological behaviors of the obtained hydrothermal reduced graphene oxide coating by AFM tester were then investigated under various testing circumstances. The results showed that the coating performed reliable and low adhesion and friction forces under all circumstances. The nanowear resistance of the titanium substrate was significantly strengthened by the prepared coating.

scholarly journals Preparation of hydrophobic fabrics and effect of fluorine monomers on surface properties

2019 ◽  
Vol 14 ◽  
pp. 155892501988961
Author(s):  
Liping Liang ◽  
Manuel J Lis Arias ◽  
Zixuan Lou ◽  
Qiaole Mao ◽  
Chang Ye ◽  
...  
Keyword(s):  
Contact Angle ◽  
Water Contact Angle ◽  
Cotton Fabric ◽  
Self Assembly ◽  
Chemical Structure ◽  
Research Work ◽  
Polymerization Reaction ◽  
Hydrophobic Property ◽  
Water Contact ◽  
Assembly Method

Preparation of hydrophobic cotton fabric based on the self-assembly method was proposed. The cotton fabric was modified with 3-(methacryloyloxy)propyltrimethoxysilane and grafted with trifluoroethyl methacrylate and dodecafluoroheptyl methacrylate through free radical polymerization reaction. The objective of this research work was to investigate the effect of fluorine monomer with different chemical structure deposited on cotton fabric on the hydrophobic property. The chemical structure, surface topography, and surface wettability of the fabrics were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and water contact angle experiments, respectively. The results showed that the as-prepared fabrics exhibited water contact angle of above 140°. It was noticed that the fluorocarbon chain length of a modifier and its chemical structure could strongly affect the hydrophobic property of the modified fabrics, and the increase in fluorine atoms caused an increase in the water contact angle values.

Fabrication and Properties of the PVDF/PVDF-g-PMMA Blend Hydrophilic Membrane

2011 ◽  
Vol 418-420 ◽  
pp. 639-642
Author(s):  
Tao Yuan ◽  
Jian Qiang Meng ◽  
Guo Rong Cai ◽  
Yu Feng Zhang
Keyword(s):  
Contact Angle ◽  
Water Contact Angle ◽  
Polyvinylidene Fluoride ◽  
Membrane Surface ◽  
Pure Water ◽  
Water Flux ◽  
Water Contact ◽  
H Nmr ◽  
Membrane Surfaces ◽  
Static Water

An amphiphilic graft copolymer was obtained via atom transfer radical polymerization (ATRP) of methacrylate (MMA) initiated directly by polyvinylidene fluoride (PVDF). Hydrophilic PVDF membranes were prepared by immersion precipitation of PVDF-g-PMMA and PVDF blend solutions. The chemical structure and the molecular weight were characterized by 1H-NMR and GPC. The hydrophilicity of membrane surfaces were characterized by static water contact angle. Top surface and cross-section of membranes were observed by Field Emission Scanning Electron Microscope (FESEM). The results demonstrated the water contact angle of the membrane surface decreased from 89°to 67°, indicating enhanced hydrophilicity; the pure water flux water firstly decreased and then increased up to 1.7 times of the PVDF membrane. The retention of PEG (Mn=6000) could be maintained at 93%-95%.

Long-Term Stable Metal Organic Framework (MOF) Based Mixed Matrix Membranes for Ultrafiltration

2020 ◽  
Author(s):  
Muayad Al-shaeli ◽  
Stefan J. D. Smith ◽  
Shanxue Jiang ◽  
Huanting Wang ◽  
Kaisong Zhang ◽  
...  
Keyword(s):  
Contact Angle ◽  
Water Contact Angle ◽  
Mixed Matrix Membranes ◽  
Recovery Ratio ◽  
Mixed Matrix ◽  
Water Contact ◽  
Membrane Performance ◽  
Metal Organic ◽  
Matrix Membranes

<p>In this study, novel <a>mixed matrix polyethersulfone (PES) membranes</a> were synthesized by using two different kinds of metal organic frameworks (MOFs), namely UiO-66 and UiO-66-NH<sub>2</sub>. The composite membranes were characterised by SEM, EDX, FTIR, PXRD, water contact angle, porosity, pore size, etc. Membrane performance was investigated by water permeation flux, flux recovery ratio, fouling resistance and anti-fouling performance. The stability test was also conducted for the prepared mixed matrix membranes. A higher reduction in the water contact angle was observed after adding both MOFs to the PES and sulfonated PES membranes compared to pristine PES membranes. An enhancement in membrane performance was observed by embedding the MOF into PES membrane matrix, which may be attributed to the super-hydrophilic porous structure of UiO-66-NH<sub>2</sub> nanoparticles and hydrophilic structure of UiO-66 nanoparticles that could accelerate the exchange rate between solvent and non-solvent during the phase inversion process. By adding the MOFs into PES matrix, the flux recovery ratio was increased greatly (more than 99% for most mixed matrix membranes). The mixed matrix membranes showed higher resistance to protein adsorption compared to pristine PES membranes. After immersing the membranes in water for 3 months, 6 months and 12 months, both MOFs were stable and retained their structure. This study indicates that UiO-66 and UiO-66-NH<sub>2</sub> are great candidates for designing long-term stable mixed matrix membranes with higher anti-fouling performance.</p>

scholarly journals Surface modification of PMMA polymer and its composites with PC61BM fullerene derivative using an atmospheric pressure microwave argon plasma sheet

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Andrzej Sikora ◽  
Dariusz Czylkowski ◽  
Bartosz Hrycak ◽  
Magdalena Moczała-Dusanowska ◽  
Marcin Łapiński ◽  
...  
Keyword(s):  
Contact Angle ◽  
Surface Modification ◽  
Chemical Composition ◽  
Water Contact Angle ◽  
Plasma Sheet ◽  
Atmospheric Pressure ◽  
Argon Plasma ◽  
Fullerene Derivative ◽  
Water Contact ◽  
Pmma Polymer

AbstractThis paper presents the results of experimental investigations of the plasma surface modification of a poly(methyl methacrylate) (PMMA) polymer and PMMA composites with a [6,6]-phenyl-C61-butyric acid methyl ester fullerene derivative (PC61BM). An atmospheric pressure microwave (2.45 GHz) argon plasma sheet was used. The experimental parameters were: an argon (Ar) flow rate (up to 20 NL/min), microwave power (up to 530 W), number of plasma scans (up to 3) and, the kind of treated material. In order to assess the plasma effect, the possible changes in the wettability, roughness, chemical composition, and mechanical properties of the plasma-treated samples’ surfaces were evaluated by water contact angle goniometry (WCA), atomic force microscopy (AFM), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). The best result concerning the water contact angle reduction was from 83° to 29.7° for the PMMA material. The ageing studies of the PMMA plasma-modified surface showed long term (100 h) improved wettability. As a result of plasma treating, changes in the samples surface roughness parameters were observed, however their dependence on the number of plasma scans is irregular. The ATR-FTIR spectra of the PMMA plasma-treated surfaces showed only slight changes in comparison with the spectra of an untreated sample. The more significant differences were demonstrated by XPS measurements indicating the surface chemical composition changes after plasma treatment and revealing the oxygen to carbon ratio increase from 0.1 to 0.4.

scholarly journals Physicochemical Properties and Biocompatibility of Electrospun Polycaprolactone/Gelatin Nanofibers

2021 ◽  
Vol 18 (9) ◽  
pp. 4764
Author(s):  
Wei Lee Lim ◽  
Shiplu Roy Chowdhury ◽  
Min Hwei Ng ◽  
Jia Xian Law
Keyword(s):  
Contact Angle ◽  
Physicochemical Properties ◽  
Water Contact Angle ◽  
Ligament Injury ◽  
Great Promise ◽  
Composition Analysis ◽  
Water Contact ◽  
Tenogenic Differentiation ◽  
Good Biocompatibility ◽  
Tissue Grafts

Tissue-engineered substitutes have shown great promise as a potential replacement for current tissue grafts to treat tendon/ligament injury. Herein, we have fabricated aligned polycaprolactone (PCL) and gelatin (GT) nanofibers and further evaluated their physicochemical properties and biocompatibility. PCL and GT were mixed at a ratio of 100:0, 70:30, 50:50, 30:70, 0:100, and electrospun to generate aligned nanofibers. The PCL/GT nanofibers were assessed to determine the diameter, alignment, water contact angle, degradation, and surface chemical analysis. The effects on cells were evaluated through Wharton’s jelly-derived mesenchymal stem cell (WJ-MSC) viability, alignment and tenogenic differentiation. The PCL/GT nanofibers were aligned and had a mean fiber diameter within 200–800 nm. Increasing the GT concentration reduced the water contact angle of the nanofibers. GT nanofibers alone degraded fastest, observed only within 2 days. Chemical composition analysis confirmed the presence of PCL and GT in the nanofibers. The WJ-MSCs were aligned and remained viable after 7 days with the PCL/GT nanofibers. Additionally, the PCL/GT nanofibers supported tenogenic differentiation of WJ-MSCs. The fabricated PCL/GT nanofibers have a diameter that closely resembles the native tissue’s collagen fibrils and have good biocompatibility. Thus, our study demonstrated the suitability of PCL/GT nanofibers for tendon/ligament tissue engineering applications.

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