Investigation of wettability and moisture sorption property of electrospun poly(N-isopropylacrylamide) nanofibers

MRS Advances ◽  
2016 ◽  
Vol 1 (27) ◽  
pp. 1959-1964 ◽  
Author(s):  
Anupama Sargur Ranganath ◽  
V. Anand Ganesh ◽  
Kostiantyn Sopiha ◽  
Rahul Sahay ◽  
Avinash Baji

ABSTRACTPoly(N-isopropylacrylamide) (PNIPAM) has been used extensively for numerous biomedical applications. However, there is not enough information in the literature on the wettability and hygroscopic properties of electrospun PNIPAM fibers, relevant for water harvesting applications. This study focuses on investigating the wettability and hygroscopic properties of electrospun PNIPAM fibers at room temperature and elevated temperature. The wettability properties of electrospun PNIPAM fibers were compared to spin-coated PNIPAM thin films. The wettability properties of the electrospun fibers were enhanced by 56% compared to spin-coated films. Water contact angle (WCA) measured on electrospun fibers was determined to be 137° at elevated temperatures while WCA on spin cast PNIPAM film was determined to be 81° at elevated temperatures. Furthermore, hygroscopic properties of the electrospun PNIPAM fibers were studied using thermogravimetric analysis (TGA). The PNIPAM fibers are seen to exhibit moisture absorption capacity of about 16.6 wt. % under humid conditions.

2021 ◽  
Author(s):  
Yufei Zhang ◽  
Lei Wu ◽  
Xinglei Zhao ◽  
Xianfeng Wang ◽  
Jianyong Yu ◽  
...  

Abstract Honeycomb-like nanofibrous membranes (NFMs) are promising nanomaterials that can be used in tissue engineering, drug delivery, and water harvesting; however, enhancing the mechanical properties of these nanomaterials has proven extremely challenging. Herein, we report a biomimetic, super-flexible, highly elastic, and tough NFM-based water/fog harvester with a highly-ordered gradient honeycomb-like network structure self-assembled from electrospun spider-silk-like humped nanofibers. The resultant NFM exhibits super flexibility, strengthening (2.9 MPa), high elasticity, and toughening (3.39 MJ m− 3), allowing it to be used as the framework of hygroscopic materials. The resulting hygroscopic NFM displays excellent moisture absorption performance. It can be used as a water/fog harvester with superhigh equilibrium moisture absorption capacity of 4.60 g g− 1 at 95% RH, fast moisture absorption and transport rates, and long-term durability, achieving directional transport and collection of tiny water droplets. This work paves the way for the design and development of multifunctional NFMs with gradient honeycomb-like network structure.


2019 ◽  
Vol 16 (152) ◽  
pp. 20180955 ◽  
Author(s):  
Weigeng Wang ◽  
C. J. Luo ◽  
Jie Huang ◽  
Mohan Edirisinghe

We develop a simple, fast and economical surface treatment under ambient temperature to improve the hydrophilicity and osteoconductivity of polyetheretherketone (PEEK) for bone implant applications. A major challenge in bone implants is the drastic difference in stiffness between traditional implant materials (such as titanium and stainless steel) and human bone. PEEK is biocompatible with an elastic modulus closely matching that of human bone, making it a highly attractive alternative. However, its bio-inert and poorly hydrophilic surface presents a serious challenge for osseointegration. Sulfonation can improve hydrophilicity and introduce bioactive sulfonate groups, but PEEK sulfonation has traditionally been applied for fuel cells, employing elevated temperatures and long reaction times to re-cast PEEK into sulfonated films. Little research has systematically studied PEEK surface modification by short reaction time (seconds) and ambient-temperature sulfonation for biomedical applications. Here, we investigate three ambient-temperature sulfonation treatments under varying reaction times (5–90 s) and evaluate the hydrophilicity and morphology of 15 modified PEEK surfaces. We establish an optimal treatment using 30 s H 2 SO 4 followed by 20 s rinsing, and then 20 s immersion in NaOH followed by 20 s rinsing. This 30 s ambient-temperature sulfonation is found to be more effective than conventional plasma treatments and reduced PEEK water contact angle from 78° to 37°.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jiaqi Wang ◽  
Yan Chen ◽  
Qinyao Xu ◽  
Miaomiao Cai ◽  
Qian Shi ◽  
...  

AbstractSuperhydrophobic sponges have considerable potential for oil/water separation. Most of the methods used for superhydrophobic modification of sponges require toxic or harmful solvents, which have the drawbacks of hazardous to environment, expensive, and complex to utilize. Moreover, the hydrophobic layer on the surface of sponge is often easily destroyed. In this paper, a highly efficient superhydrophobic sponge with excellent reusability was developed by using a facile, simple and environmentally friendly dopamine biomimetic bonding method. Different types of sponges, such as melamine, polyethylene or polyurethane sponge wastes, were used as raw materials to prepare superhydrophobic sponges, which possess the advantages of inexpensive and abundant. The effects of different dopamine polymerization time and different hydrophobic agent dosage on the hydrophobicity and oil absorption capacity of melamine sponges were optimized. The study results showed that the water contact angle of the superhydrophobic sponge could reach 153° with excellent organic solvent absorption capacity of 165.9 g/g. Furthermore, the superhydrophobic sponge retained approximately 92.1% of its initial absorption capacity after 35 reutilization cycles. More importantly, the dopamine biomimetic bonding superhydrophobic modification method can be used for different types of sponges. Therefore, a universally applicable, facile, simple and environmentally friendly superhydrophobic modification method for sponges was developed.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ahmed S. Belal ◽  
Jehan El Nady ◽  
Azza Shokry ◽  
Shaker Ebrahim ◽  
Moataz Soliman ◽  
...  

AbstractOily water contamination has been sighted as one of the most global environmental pollution. Herein, copper hydroxide nanorods layer was constructed onto cellulosic filter paper surface cured with polydopamine, Ag nanoparticles, and Cu NPs through immersion method. This work has been aimed to produce a superhydrophobic and superoleophilic cellulosic filter paper. The structure, crystalline, and morphological properties of these modified cellulosic filter paper were investigated. Scanning electron microscope images confirmed that the modified surface was rougher compared with the pristine surface. The contact angle measurement confirmed the hydrophobic nature of these modified surfaces with a water contact angle of 169.7°. The absorption capacity was 8.2 g/g for diesel oil and the separation efficiency was higher than 99%. It was noted that the flux in the case of low viscosity solvent as n-hexane was 9663.5 Lm−2 h−1, while for the viscous oil as diesel was 1452.7 Lm−2 h−1.


Author(s):  
Jesús A. Claudio-Rizo ◽  
Nallely Escobedo-Estrada ◽  
Sara L. Carrillo-Cortes ◽  
Denis A. Cabrera-Munguía ◽  
Tirso E. Flores-Guía ◽  
...  

AbstractDeveloping new approaches to improve the swelling, degradation rate, and mechanical properties of alginate hydrogels without compromising their biocompatibility for biomedical applications represents a potential area of research. In this work, the generation of interpenetrated networks (IPN) comprised from alginate–polyurethane in an aqueous medium is proposed to design hydrogels with tailored properties for biomedical applications. Aqueous polyurethane (PU) dispersions can crosslink and interpenetrate alginate chains, forming amide bonds that allow the structure and water absorption capacity of these novel hydrogels to be regulated. In this sense, this work focuses on studying the relation of the PU concentration on the properties of these hydrogels. The results indicate that the crosslinking of the alginate with PU generates IPN hydrogels with a crystalline structure characterized by a homogeneous smooth surface with high capacity to absorb water, tailoring the degradation rate, thermal decomposition, and storage module, not altering the native biocompatibility of alginate, providing character to inhibit the growth of E. coli and increasing also its hemocompatibility. The IPN hydrogels that include 20 wt.% of PU exhibit a reticulation index of 46 ± 4%, swelling capacity of 545 ± 13% at 7 days of incubation at physiological pH, resistance to both acidic and neutral hydrolytic degradation, mechanical improvement of 91 ± 1%, and no cytotoxicity for monocytes and fibroblasts growing for up to 72 h of incubation. These results indicate that these novel hydrogels can be used for successful biomedical applications in the design of wound healing dressings.


2021 ◽  
pp. 004051752098497
Author(s):  
Ning Mao ◽  
Xiaohong Qin ◽  
Liming Wang ◽  
Jianyong Yu

Wet comfort is a critical performance for fabrics, especially when human bodies release sweat in daily life. Despite excellent moisture absorption performance, cotton yarns are still limited in the moisture release/transfer ability. Here, based on a novel electrospinning technology, polyacrylonitrile and polystyrene (PS) electrospun nanofiber/cotton composite yarns were produced, respectively. Under fluorescence microscopic observation, electrospun fibers within the composite yarns showed a uniform distribution. As a result, these composite yarn-based knitted fabrics obtained a good water transport ability and a fast water evaporation rate. According to the moisture management test, PS electrospun nanofiber composite yarn-based fabrics exhibited a relatively high one-way transport index R (400%), claiming an enhanced moisture management performance. Finally, specific surface area tests and finite element analyses were used to analyze the water transport mechanism inside the yarns. The results proved that a small number of electrospun fibers played a predominant role in enhancing the moisture management ability of the composite yarns.


Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2896
Author(s):  
Sara Ferraris ◽  
Silvia Spriano ◽  
Alessandro Calogero Scalia ◽  
Andrea Cochis ◽  
Lia Rimondini ◽  
...  

Electrospinning is gaining increasing interest in the biomedical field as an eco-friendly and economic technique for production of random and oriented polymeric fibers. The aim of this review was to give an overview of electrospinning potentialities in the production of fibers for biomedical applications with a focus on the possibility to combine biomechanical and topographical stimuli. In fact, selection of the polymer and the eventual surface modification of the fibers allow selection of the proper chemical/biological signal to be administered to the cells. Moreover, a proper design of fiber orientation, dimension, and topography can give the opportunity to drive cell growth also from a spatial standpoint. At this purpose, the review contains a first introduction on potentialities of electrospinning for the obtainment of random and oriented fibers both with synthetic and natural polymers. The biological phenomena which can be guided and promoted by fibers composition and topography are in depth investigated and discussed in the second section of the paper. Finally, the recent strategies developed in the scientific community for the realization of electrospun fibers and for their surface modification for biomedical application are presented and discussed in the last section.


Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1593 ◽  
Author(s):  
Hajo Yagoub ◽  
Liping Zhu ◽  
Mahmoud H. M. A. Shibraen ◽  
Ali A. Altam ◽  
Dafaalla M. D. Babiker ◽  
...  

The complex aerogel generated from nano-polysaccharides, chitin nanocrystals (ChiNC) and TEMPO-oxidized cellulose nanofibers (TCNF), and its derivative cationic guar gum (CGG) is successfully prepared via a facile freeze-drying method with glutaraldehyde (GA) as cross-linkers. The complexation of ChiNC, TCNF, and CGG is shown to be helpful in creating a porous structure in the three-dimensional aerogel, which creates within the aerogel with large pore volume and excellent compressive properties. The ChiNC/TCNF/CGG aerogel is then modified with methyltrichlorosilane (MTCS) to obtain superhydrophobicity/superoleophilicity and used for oil–water separation. The successful modification is demonstrated through FTIR, XPS, and surface wettability studies. A water contact angle of 155° on the aerogel surface and 150° on the surface of the inside part of aerogel are obtained for the MTCS-modified ChiNC/TCNF/CGG aerogel, resulting in its effective absorption of corn oil and organic solvents (toluene, n-hexane, and trichloromethane) from both beneath and at the surface of water with excellent absorption capacity (i.e., 21.9 g/g for trichloromethane). More importantly, the modified aerogel can be used to continuously separate oil from water with the assistance of a vacuum setup and maintains a high absorption capacity after being used for 10 cycles. The as-prepared superhydrophobic/superoleophilic ChiNC/TCNF/CGG aerogel can be used as a promising absorbent material for the removal of oil from aqueous media.


Author(s):  
Л.В. АНТИПОВА ◽  
С.А. ТИТОВ ◽  
И.В. СУХОВ

Исследовано взаимодействие коллагена пресноводных рыб с водой для повышения его водопоглощающей способности. Объектом исследования был вторичный продукт переработки рыбного сырья – шкуры прудовых рыб, преимущественно толстолобика. Для исследования были использованы методы термогравиметрии и дифференциальной сканирующей калориметрии. Измерения проведены на приборе синхронного термического анализа модели STA 449 F3 Jupiter. Установлено, что основная доля влаги связывается адсорбционным или осмотическим путем, а на долю капиллярной влаги приходится всего 7% массы воды, связанной образцами. Большая величина энергии связи адсорбции – 4 Дж/моль свидетельствует о способности функциональных групп коллагена к созданию гидратной оболочки, содержащей значительное количество воды. Для увеличения влагопоглощающей способности необходимо разрыхление коллагеновых волокон, что увеличивается свободный доступ влаги к фибриллам белка, увеличивающим впитывание влаги. Для эффективного разрыхления предложено выдерживать шкуры толстолобика в растворе органических кислот концентрацией 0,5%. Это позволяет добиться высокой влагоемкости, которая достигает 35–40 объемов влаги на 1 единицу массы исследуемого материала, что делает перспективным использование коллагена в качестве материала для впитывающих влагу слоев средств личной гигиены, одежды, обуви. The interaction of freshwater fish collagen with water to increase its water absorption capacity was studied. The secondary product of processing of fish raw materials – skins of pond fish, mainly silver carp, was the object of study. Methods of thermogravimetry and differential scanning calorimetry were used for the study. Measurements were carried out on the device of synchronous thermal analysis of model STA 449 F3 Jupiter. It was found that the bulk of the moisture is bound by adsorption or osmotic way, and 7% of mass of the water connected by samples fall to the share of capillary moisture. A large amount of adsorption binding energy – 4 J/mol indicates the ability of collagen functional groups to create a hydrated shell containing a significant amount of water. Loosening of collagen fibers is necessary to increase the moisture absorption capacity, which will increase the free access of moisture to the protein fibrils, increasing the absorption of moisture. It is proposed to withstand the skins of silver carp in a solution of organic acids with a concentration of 0,5% for effective loosening. This makes it possible to achieve high moisture capacity, which reaches 35–40 volumes of moisture per 1 unit mass of the test material, which makes it promising to use collagen as a material for moisture-absorbing layers of personal hygiene products, clothing, and shoes.


2016 ◽  
Vol 869 ◽  
pp. 930-934
Author(s):  
Cristiane Mayumi Wada ◽  
André Luiz Reis Rangel ◽  
Marisa Aparecida de Souza ◽  
Rosemeire dos Santos Almeida ◽  
Marcos Akira D’Ávila ◽  
...  

In this study, PCL electrospun fibers were deposited on the Ti-30Ta alloy for change the surface properties. Experimental Ti-30Ta alloy was obtained by melting titanium and tantalum in arc melting furnace with argon atmosphere. Ingots were homogenized and bars with 10 mm of diameter were obtained in rotative swagging. PCL fibers were deposited on disks of the alloy by electrospinning. Plasma treatment was carried out for change PCL electrospun superficial energy by using stainless steel plasma reactor. Samples were immersed in mineralization solution for apatite growth. Surfaces were evaluated by using SEM, X-rays diffraction and contact angle. Samples exhibited hydrophilic behavior after plasma treatment and mineralization. Results are very interesting for biomedical applications.


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