Networks with Fiber Surface Interactions

Multiphase fluids that contain dispersed oil droplets are fundamental to many industrial processes and formulated products. In the present work, the surface wetting and interaction between an emulsion droplet and a single fibre were quantitatively investigated as a function of surfactant chemistry, pH, and salt concentration using an optical tweezers apparatus. Silicone droplets were emulsified in water and stabilised by surfactants. An individual droplet was captured using an optical tweezers setup to allow a controlled contact with a fibre surface. During the approach process, the surface interaction was measured and spreading behaviour was quantified after contact was made between the droplet and fibre. Salt concentration was increased to change the surface interaction behaviour. The pH and ζ-potential of silicone emulsions decreased from 9.5 to 6.0 and from 39 mV to − 15 mV, respectively, when increasing salt concentration for both of the surfactants studied, SDS and CTAB. The attraction between the fibre and a silicone oil droplet was found to increase as the electrostatic repulsion was suppressed with an increased salt concentration. This was confirmed by an increased number of droplet-fibre adhesion events and in some cases droplet spreading on the fibre. Such observations for adhesion are based on electrostatic attractions exceeding the maximum force that can be exerted by the trapping laser. When adhesion was not observed, attraction could still be recorded through a thin-film hydrodynamic suction effect during the process of retraction, which becomes more pronounced on the polyester fibre. Our results provide a novel method to directly quantify the surface interaction and wetting of liquid droplets on microscopic fibres simultaneously, which could be valuable when investigating formulated products that involve emulsion droplets.

The wettability of glass, carbon, and organic fillers (in the form of fibres or fabrics) by powder thermoplastic polymers has been studied. Wettability is the first step in the interaction between the components, a necessary condition for forming an interface, so as to achieve high levels of physico-mechanical properties of plastic laminates. Dependences were obtained of the wetting parameters on the particle size, which is the primary characteristic of powder polymers, and on the chemistry of the polymer and on the time-temperature parameters of the prepreg fabrication. The molecular weight of the polymer was observed to influence the wetting kinetics and spreading behaviour of molten thermoplastics.

PM collection performance of electret filters electrospun with different dielectric materials-a numerical modeling and experimental study

The filtration efficiency of electrospun PC membrane was higher than those of both PVA and PS membranes, suggesting that polarity is the most influential factor shaping the interaction of particles and fiber surfaces.

Study of the interaction of carbon fibre surfaces with a monofunctional epoxy resin

The objective of this review is to elucidate the rheological behavior of glass fiber suspensions whose suspending mediums are non-Newtonian fluids. In particular, this review focuses on determining the impact of fiber concentration, aspect ratio, orientation distribution, interaction with the suspending medium, and suspending medium viscoelasticity on the rheology of glass fiber composite fluids. The presence of glass fiber can induce a yieldlike behavior, causing shear thinning to occur at reduced shear rates. Glass fiber can impede the elastic properties of the suspending medium but enhance the first normal stress function. Large stress overshoots in both the shear and normal stress growth functions are observed that are associated with changes in fiber orientation. Upon cessation of flow, stress relaxation follows that of the suspending medium but fibers retain their orientation. The presence of glass fiber can induce extension rate thinning and suppress the strain thickening behavior of the suspending medium. 1. Introduction Glass fibers have been used for decades to improve the mechanical, thermal, and insulative properties of polymers. 1 These property improvements are highly dependent on the orientation distribution of the glass fiber. This makes it desirable to be able to predict not only the rheological behavior of the composite fluid but also the orientation of the fiber generated during processing. Understanding the rheological behavior of polymeric fluids containing glass fibers is essential to model development. With respect to the fiber, it is of interest to understand the role of concentration and aspect ratio and their relation to the degree of interparticle interaction (fiber -fiber) as well as orientation distribution and interaction with the suspending medium. With respect to the suspending medium, it is of interest to understand the role of viscoelasticity and how it is affected by the presence of the fibers. The rheological properties of glass fiber suspensions in Newtonian suspending mediums has been reviewed in detail by Ganani and Powell 2 and Zirnsak et al. 3 and will be referred to in this review for comparison purposes only. The primary focus of this review is to elucidate the rheological properties of glass fiber suspensions in non-Newtonian fluids of various degrees of viscoelasticity with an emphasis on composite fluids. Before reviewing the rheology, it is imperative to have a basic understanding of glass fiber suspensions, the rheometers used to characterize them, and any extra forces that can lead to mechanisms for changes in the fiber microstructure. For this reason, subsequently, we will briefly discuss the use of surface treatments to increase the interaction with the matrix. We then classify fiber suspensions by their concentration and length. This is followed by a review of the different rheometers and rheometer geometries used to characterize glass fiber suspensions, including a discussion of their strengths and weaknesses with respect to obtaining accurate measurements of rheological material functions. Last, we discuss and estimate the contribution of Brownian motion and gravity (relating to particle sedimentation) to changes in fiber orientation within the suspension. 1.1. Surface Modifications. The surface of a glass fiber is typically modified for two reasons: to minimize the selfdestructive abrasive contact between the fibers and to increase the fiber-matrix interaction of the melt and the adhesive strength of the composite. The use of “sizing” as a surface treatment has become an industrial standard and addresses both the abrasive contact and the surface interaction. Sizing is a functional coating that acts as an abrasive barrier that is tailored

Despite the importance of adhesion between electrospun meshes and substrates, the knowledge on adhesion mechanism and the method to improve the adhesion remain limited. Here, we precisely design the model system based on electrospun poly(ethylene oxide) (PEO) meshes and the substrate of styrene-b-(ethylene-co-butylene)-b-styrene elastomer (SEBS), and quantitatively measure the adhesion with a weight method. The surfaces of SEBS with different roughness are obtained by casting SEBS solution on the smooth and rough glass slides, respectively. Then, the surfaces of casted SEBS are respectively grafted with PEG oligomers and long PEG chains much larger than the entanglement molecular weight by surface-initiated atom transfer radical polymerization (SI-ATRP) of poly(ethylene glycol) methyl ether methacrylate (PEGMA). The detached surfaces of SEBS and electrospun fibers after adhesion measurements are analyzed by scanning electron microscopy (SEM). The adhesive force and adhesion energy are found to lie in the range from 68 to 220 mN and from 12 to 46 mJ/m(2), respectively, which are slightly affected by surface roughness of substrate but mainly determined by surface interactions. Just as the chemical cross-linking induces the strong adhesion, the chain entanglements on the interface lead to the higher adhesion than those generated by hydrophilic-hydrophobic interactions and hydrophilic interactions. The long grafted chains and the enhanced temperature facilitate the chain entanglements, resulting in the strong adhesive force. This work sheds new light on the adhesion mechanism at molecular level, which may be helpful to improve the adhesion between the electrospun fibers and substrates in an environmentally friendly manner.

The purpose of the present work is to investigate the effects of helium plasma treatment on tensile deformation of nano-SiO2 sol-gel coating T300 carbon fiber and provide a new concept for the nano-structural interphase between fiber surface and nano-coating. The tensile test results show that the activation volumes of T300 carbon fibers untreated and treated with helium plasma ranging from 681.9628 to 32342 nm3 by following Eyrings equation are important descriptors for the properties of the nano-structural interface between fiber surface and nano-coating, and the ductility of the nano-SiO2 sol-gel coating T300 carbon fibers treated by helium plasma is enhanced. From the results of the scanning electron microscope, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy, it is found that the uniform dispersion of the nano-SiO2 coating of the T300 carbon fibers treated by helium plasma can not only fill the micro-flaws, but also cause the occurrence of effective activation surface interaction between carbon fibers and nano-SiO2 coating, along with the introduced activated functional groups on the fiber surfaces.

Surface Modification and its Effect on Fiber Surface and Matrix Interactions

The apparent increase in hormone-induced cancers and disorders of the reproductive tract has led to a growing demand for new technologies capable of detecting endocrine disruptors. However, a long-lasting challenge unaddressed is how to achieve ultrahigh sensitive, continuous, and in situ measurement with a portable device for in-field and remote environmental monitoring. Here we demonstrate a simple-to-implement plasmonic optical fiber biosensing platform to achieve an improved light–matter interaction and advanced surface chemistry for ultrasensitive detection of endocrine disruptors. Our platform is based on a gold-coated highly tilted fiber Bragg grating that excites high-density narrow cladding mode spectral combs that overlap with the broad absorption of the surface plasmon for high accuracy interrogation, hence enabling the ultrasensitive monitoring of refractive index changes at the fiber surface. Through the use of estrogen receptors as the model, we design an estradiol–streptavidin conjugate with the assistance of molecular dynamics, converting the specific recognition of environmental estrogens (EEs) by estrogen receptor into surface-based affinity bioassay for protein. The ultrasensitive platform with conjugate-induced amplification biosensing approach enables the subsequent detection for EEs down to 1.5 × 10−3 ng ml−1 estradiol equivalent concentration level, which is one order lower than the defined maximal E2 level in drinking water set by the Japanese government. The capability to detect EEs down to nanogram per liter level is the lowest limit of detection for any estrogen receptor-based detection reported thus far. Its compact size, flexible shape, and remote operation capability open the way for detecting other endocrine disruptors with ultrahigh sensitivity and in various hard-to-reach spaces, thereby having the potential to revolutionize environment and health monitoring.

Use of Nitroxides as Topological Monitors of the Interaction of Silica-Based Particles with Components of the Biological Environment

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.

2D graphene oxide and MXene nanosheets at carbon fiber surfaces

The present investigation focuses on the effect of fiber surface treatment on the mechanical, thermal and morphological properties of sisal fiber (SF) reinforced recycled polypropylene (RPP) composites. The surface of sisal fiber was modified using different chemicals such as silane, glycidyl methacrylate (GMA) and O-hydroxybenzene diazonium chloride (OBDC) to improve the compatibility between fiber surface and polymer matrix. The experimental results revealed an improvement in the tensile strength to 11 %, 20 % and 31.36 % and impact strength to 78.72 %, 77 % and 81 % for silane, GMA and OBDC treated sisal fiber reinforced recycled polypropylene (RPP/SF) composites respectively as compared to RPP. The thermo gravimetric analysis (TGA), Differential scanning calorimeter (DSC) and heat deflection temperature (HDT) results revealed improved thermal stability as compared with RPP. The morphological analysis through scanning electron micrograph (SEM) supports improves surface interaction between fiber surface and polymer matrix.

Seed-assisted hydrothermal fabrication of nanostructured boehmite coating on carbon fiber