Reshaping teaching strategies for innovative materials in art and design

Textiles have faced a new challenge with the advancement of electronics and nanotechnology. Smart textiles represented the newest stage of the technological revolution, which is grounded in new fibre materials and textile manufacturing processes for fabrics exhibiting additional functionalities. These fabrics have been engineered to see, hear, sense, communicate, store and convert energy, and even tune colour. This multi-disciplinary field includes end-to-end prototyping from fibre design to system integration of new textile based products, and also requires to comprehend the underpinnings of material science and nanotechnology. Classical teaching methods are not effective enough to engage and motivate students with art and design background. The real question is, “How do you teach smart textiles in graduate level, especially to the students who never studied quantum mechanics, differential equations and fluid dynamics before?” This study outlines reshaping teaching strategies for innovative and tangible materials in art and design education, and addresses the importance of student-led experiences in research projects and integration of hands-on learning

Molecular basis for solvent dependent morphologies observed on electrosprayed surfaces

We study the causes of the observed tunable hydrophobicity of poly(styrene-co-perfluoroalkyl ethylacrylate) electrosprayed in THF, DMF, and THF : DMF (1 : 1) solvents. Under the assumption that equilibrium morphologies in the solvent significantly affect the patterns observed on electrosprayed surfaces, we use atomistic and coarse-grained simulations supported by dynamic light scattering (DLS) experiments to focus on the parameters that affect the resulting morphology of superhydrophobic electrosprayed beads. The differing equilibrium chain size distributions in these solvents examined by DLS are corroborated by chain dimensions obtained via molecular dynamics simulations. Mesoscopic morphologies monitored by dissipative particle dynamics simulations explain experimental observations; in particular, the preference of the polymer for THF over DMF in the binary mixture rationalizes the dual scale roughness driven by stable microphase separation. Drying phenomena that affect resultant dual-scale roughness are described in three stages, each interpreted by concentration dependent diffusion and surface mass transfer coefficients of the solvents. Irrespective of the presence of polar groups in the structure, a conflict between the lower-boiling point solvent adhering to the polymer and the less volatile solvent abundant in the bulk leads to perfectly hydrophobic surfaces

Polyacrylonitrile (PAN)/crown ether composite nanofibers for the selective adsorption of cations

In this study, we prepared electrospun polyacrylonitrile (PAN) nanofibers functionalized with dibenzo-18-crown-6 (DB18C6) crown ether and showed the potential of these fibers for the selective recovery of K+ from other both mono- and divalent ions in aqueous solutions. Nanofibers were characterized by SEM, FTIR and TGA. SEM results showed that the crown ether addition resulted in thicker nanofibers and higher mean fiber diameters, in a range of 138 to 270 nm. Batch adsorption experiments were conducted in order to evaluate the potential of the crown ether modified nanofibers as an adsorbent for ion removal. The maximum adsorption capacity of the crown ether modified nanofibers for K+ was 0.37 mmol g−1 and the nanofibers followed the selectivity sequence of K+ > Ba2+ > Na+ ∼ Li+ for single ion experiments. Adsorption of Ba2+ ions onto crown ether-modified nanofiber was examined by XPS and the results confirmed the adsorption of the ion. Mixed ion adsorption experiments revealed competitive adsorption between K+ and Ba2+ ions for the available binding sites. This effect was not observed for the other monovalent ions present in the solution and exceptionally high selectivities for K+ over Li+ and Na+ were obtained. Also the crown ether modified nanofibers exhibited good regeneration properties and a good reusability over multiple consecutive adsorption–desorption cycles. Electrospinning is thus shown to be a very versatile tool to prepare crown ether functional polymer adsorbents for the selective recovery of ions

The stability and dispersion of carbon nanotube-polymer solutions: A molecular dynamics study

Carbon nanotubes have been explored to increase the mechanical properties and electrical conductivity of polymeric fibers through compounding with polymer to be extruded into fibers. However, this route creates major challenges because carbon nanotubes have strong cohesion and tend to aggregate and precipitate due to their poor interfacial interaction with polymers. In this study, classical molecular dynamics simulations are used to predict and characterize carbon nanotubes-polymer interface mechanism in two different polymer matrices: polyvinyl butyral and polystyrene-co-glycidyl methacrylate. The dominated interface mechanisms are discovered to shed light on carbon nanotubes dispersion in solvent based systems and to explore the prerequisites for stabilized nanofluids. Our results showed that π-stacking interactions between aromatic groups and graphene surfaces of carbon nanotubes as in polystyrene-co-glycidyl methacrylate systems, play an important role in dispersion of carbon nanotubes, whereas slight repulsions between carbon nanotubes and polyvinyl butyral chains lead to large morphological differences and carbon nanotubes bundles in many chain systems. Altogether, the results indicated that polymers with structures having strong interactions with the surfaces of carbon nanotubes through π–π interactions are more effective in dispersing carbon nanotubes and caused stabilized solutions in wet fiber processing

Nanofiber-enhanced lightweight composite textiles for acoustic applications

This paper proposes lightweight textile acoustic structure, wherein electrospun polyacrylonitrile-based nanofibers enhance sound absorption properties with no weight and thickness penalty. Polyacrylonitrile nanofibers with diameter of 110 ± 7 nm were electrospun on spacer-knitted fabrics by varying deposition amount and surface coating arrangement. Proposed novel approach eliminated additional processing steps such as handling and post-lamination and provided easy scalability of nanofibers at macro-scale. The results showed that the sound absorption of nano-enhanced specimens was improved drastically when deposited amount of nanofibers or its effective surface area increased. Sound propagation paths in different configurations were interpreted from sound absorption and air permeability measurements. The sound absorption coefficient values up to 0.7 are achieved in the low and medium frequency ranges with no weight and thickness penalty by tuning deposition amount and surface coating arrangement

High strain rate response of nanofiber interlayered structural composites

Nanofibrous interlayer toughening strategy for laminated composite materials typically demonstrated at quasi-static loading is here evaluated under high strain rate deformation. Carbon fiber reinforced composite laminates of (0/90)25s stacking sequence are interlayered by polystyrene-co-glycidyl methacrylate (P(St-co-GMA)) nanofibers which are chemically tuned for interfacial compatibility when embedded in epoxy matrix. The cubical composite specimens are cut and subjected to high strain-rate deformation via Split Hopkinson pressure bar testing. Specimens are hit at their through-the-thickness (stacking) and side-to-side (in-plane) directions. The change in the dissipation of energy due to altered interlaminar microstructure is monitored and reported. Enhancement in the capacity of the energy dissipation due to the nanofibrous interlayers is as high as 80% in-plane and 40% through thickness directions, depending on the strain rate. The results overall suggest that interlayer toughening strategy used in this work prevents the formation of critical matrix cracks that can cause the formation of instantaneous mode II delamination. Incorporation of the nanofibers without causing notable weight penalty effectively toug

Mixed mode delamination in carbon nanotube/nanofiber interlayered composites

Laminated composites mostly suffer from layer separation and/or delamination, which may affect the stiffness, strength and lifetime of structures. In this study, we aim to produce micron-scale thin carbon nanotubes (CNTs) reinforced adhesive nanofibrous interleaves and to explore their effectiveness when incorporated into structural composites. Neat polyvinyl butyral (PVB) and solutions containing low fractions of CNTs from 0.5 to 2 wt.% were electrospun directly onto carbon fiber prepregs. These interlayered laminates were cured above the glass transition temperature (Tg) of PVB to achieve strong interlaminar binding and also to resist crack re-initiation. The effect of CNTs presence and their mass fractions both on total Mixed-Mode I + II fracture toughness (GC) and crack length was investigated under Mixed-Mode I + II loading. Almost 2-fold increase in GC was reported in interlayered composites compared to non-interlayered laminates, associated to toughening effect of adhesive PVB/CNTs nanofibrous interlayers. Furthermore, the post-fracture analysis revealed the aid of CNTs interleaves in retarding delamination and afterward stabilization of crack propagation

Soft Graphene-Based Antennas for Ultrawideband Wireless Communication

Ensuring user-friendliness and the seamless integration of technology into the fabric is a key challenge both for academics and industry participants. Thus, textiles that provide a seamless command-oriented user interface, and are capable of wireless communication have been an increasingly popular topic in recent years. In the field of textile antennas, patch antennas either with the use of embroidering techniques, conductive fabrics or inkjet-printing are leading the way over traditional bulky antennas. However, there are still significant problems in additive antenna fabrication such as the need to use metallic components as the conductive element which quickly becoming corroded and oxidised and also lead to high material costs. The main objective of this study is to develop graphene-based antennas for smart textiles that push the state-of-the-art in wireless body-centric systems, by utilising traditional textile manufacturing techniques. Hence, this research suggests a graphene-based antenna on a textile substrate, where the conformity of the antenna is highly desirable for wearable and body-centric applications. The designed antenna consists of a coplanar-waveguide-fed planar inverted cone-shaped patch geometry, aiming at ultrawideband antennas that work in a wide spectrum from 3.1 to 10.6GHz

Designed-in molecular interactions lead to superior thermo-mechanical properties in nanocomposites

The effect of the nanofiller chemistry on the mechanical behaviour of thermoset polymer matrix nanocomposites is investigated. The interaction between a crosslinked polymer resin and the reinforcing nanofibers driven by their chemistry is revealed by molecular dynamics simulations. Specifically, crosslinked network systems of neat epoxy and epoxy-P(St-co-GMA) are modeled to discuss the effect of various molecular interactions as a function of temperature on a molecular basis. At 433 K, incorporation of single molecule of bonded P(St-co-GMA) and nonbonded P(St-co-GMA) lead to increase in Young’s modulus by 10% and 6%, respectively, compared to neat epoxy system