Tailoring the softness performance of polyethylene/polypropylene micro‐nanofibrous fabrics for skin contacts

Scalable, Waterproof, Breathable, and Flexible Polyolefin-Elastomer/Polyethylene Glycol@Zinc Oxide Microfibrous Fabrics for Daytime Radiative Cooling Clothing

In the face of escalating global temperatures, the demand for innovative passive cooling technologies that are both low-cost and environmentally sustainable is more critical than ever. However, traditional cooling fabrics face challenges in achieving wearing comfort while maintaining breathability and durability. Herein, a novel fluffy microfibrous fabric utilizing polyolefin-elastomer and polypropylene with embedded zinc oxide nanoparticles is fabricated through melt-blown technology. The results reveal that the prepared samples demonstrate exceptional daytime radiative cooling properties that present a 12.5 °C cooling capacity under 1083 W/m2 solar radiation, highlighted by their ability to reflect up to 90.8% of solar radiation and their significantly enhanced thermal emissivity. Moreover, key findings include that the samples have robust mechanical strength, high elastic performance, and excellent antifouling capabilities, alongside superior cooling performance, which will provide an opportunity to explore the development of cooling garments for outdoor environments and contribute substantially to sustainable cooling solutions.

Effects of Erucamide on Fiber "Softness": Linking Single-Fiber Crystal Structure and Mechanical Properties

Erucamide is known to play a critical role in modifying polymer fiber surface chemistry and morphology. However, its effects on fiber crystallinity and mechanical properties remain to be understood. Here, synchrotron nanofocused X-ray Diffraction (nXRD) revealed a bimodal orientation of the constituent polymer chains aligned along the fiber axis and cross-section, respectively. Erucamide promoted crystallinity in the fiber, leading to larger and more numerous lamellae crystallites. The nXRD nanostructual characterization is complemented by single-fiber uniaxial tensile tests, which showed that erucamide significantly affected fiber mechanical properties, decreasing fiber tensile strength and stiffness but enhancing fiber toughness, fracture strain, and ductility. To correlate these single-fiber nXRD and mechanical test results, we propose that erucamide mediated slip at the interfaces between crystallites and amorphous domains during stress-induced single-fiber crystallization, also decreasing the stress arising from the shear displacement of microfibrils and deformation of the macromolecular network. Linking the single-fiber crystal structure with the single-fiber mechanical properties, these findings provide the direct evidence on a single-fiber level for the role of erucamide in enhancing fiber "softness".

Advances of polyolefins from fiber to nanofiber: fabrication and recent applications

Polyolefins are a widely accepted commodity polymer made from olefinic monomer consisting of carbon and hydrogen. This thermoplastic polymeric material is formed through reactive double bonds of olefins by the addition polymerization technique and it possesses a diverse range of unique features for a large variety of applications. Among the various types, polyethylene and polypropylene are the prominent classes of polyolefins that can be crafted and manipulated into diversified products for numerous applications. Research on polyolefins has boomed tremendously in recent times owing to the abundance of raw materials, low cost, lightweight, high chemical resistance, diverse functionalities, and outstanding physical characteristics. Polyolefins have also evidenced their potentiality as a fiber in micro to nanoscale and emerged as a fascinating material for widespread high-performance use. This review aims to provide an elucidation of the breakthroughs in polyolefins, namely as fibers, filaments, and yarns, and their applications in many domains such as medicine, body armor, and load-bearing industries. Moreover, the development of electrospun polyolefin nanofibers employing cutting-edge techniques and their prospective utilization in filtration, biomedical engineering, protective textiles, and lithium-ion batteries has been illustrated meticulously. Besides, this review delineates the challenges associated with the formation of polyolefin nanofiber using different techniques and critically analyzes overcoming the difficulties in forming functional nanofibers for the innovative field of applications.

Large-Scale Preparation of Micro-Nanofibrous and Fluffy Propylene-Based Elastomer/Polyurethane@Graphene Nanoplatelet Membranes with Breathable and Flexible Characteristics for Wearable Stretchy Heaters

Effective personal thermal management is crucial for protecting human health during cold weather. Therefore, wearable heaters based on electric-heating membranes are one of the most promising devices to become essential appliances in our daily lives. The main challenge toward this goal is the development of electric-heating membranes with adequate breathable, flexible, and stretchable characteristics. In the work presented here, micro-nanofibrous fluffy electric-heating membranes were prepared by coating polyurethane/graphene nanoplatelet (PU@GNP) films onto melt-blown propylene-based elastomer (PBE) micro-nanofibrous membranes via a facile, cheap, and large-scale method consisting of a coating-compressing cyclic process. Investigation of the resulting PBE/PU@GNP membranes showed that the PU@GNP films were uniformly deposited onto the PBE micro-nanofiber surfaces, forming fluffy interconnected conducting channels. By applying a voltage of 36 V to the prepared PBE/PU@GNP membranes, the temperature increased to 69.7 °C, confirming excellent electric-heating features. Moreover, the porosity of the fabricated membrane could be tailored readily by adjusting the coating-compressing cycles. Benefiting from the conducting channels, the PBE/PU@GNP membranes exhibited efficiently regulated air permeability ranging from 212 to 60.2 mm/s, a prominent softness score of 53.8, and an excellent elastic recovery rate of 85.5%. These findings demonstrate that PBE/PU@GNP micro-nanofibrous fluffy membranes may well be suitable for application in electric-heating clothing. The cyclic coating-compressing preparation process may be attractive in industrial manufacturing.

Facile Preparation of PET/PA6 Bicomponent Microfilament Fabrics with Tunable Porosity for Comfortable Medical Protective Clothing

Medical protective materials have broadly drawn attention due to their ability to stop the spread of infectious diseases and protect the safety of medical staff. However, creating medical protective materials that combine excellent liquid shielding performance and outstanding mechanical properties with high breathability is still a challenging task. Herein, a polyester/polyamide 6 (PET/PA6) bicomponent microfilament fabric with tunable porosity for comfortable medical protective clothing was prepared via dip-coating technology and an easy and effective thermal-belt bonding process. The dip coating of the C₆-based fluorocarbon polymer endowed the samples with excellent hydrophobicity (alcohol contact angles, 130-128°); meanwhile, by adjusting the temperature and pressure of the thermal-belt bonding process, the porosity of the samples was adapted in the range of 64.19-88.64%. Furthermore, benefitting tunable porosity and surface hydrophobicity, the samples also demonstrated an excellent softness score (24.3-34.5), agreeable air permeability (46.3-27.8 mm/s), and high hydrostatic pressure (1176-4130 Pa). Significantly, the created textiles successfully filter aerosol from the air and display highly tensile strength. These excellent comprehensive performances indicate that the prepared PET/PA6 bicomponent microfilament fabrics would be an attractive choice for medical protective apparel.

Facile Preparation of Hydrophobic PLA/PBE Micro-Nanofiber Fabrics via the Melt-Blown Process for High-Efficacy Oil/Water Separation

Polylactic acid (PLA) micro-nanofiber fabrics with a large specific surface area and excellent biodegradability are commonly used in oil/water separation; however, challenges remain due to their poor mechanical properties. Herein, a thermoplastic polylactic acid/propylene-based elastomer (PLA/PBE) polymer was prepared by blending PLA with PBE. Then, PLA/PBE micro-nanofiber fabrics were successfully prepared using a melt-blown process. The results show that the PLA/PBE micro-nanofiber fabric has a three-dimensional porous structure, improving the thermal stability and fluidity of the PLA/PBE blended polymers. The PLA/PBE micro-nanofiber fabric demonstrated a significantly reduced average fiber diameter and an enhanced breaking strength. Moreover, the water contact angle of the prepared samples is 134°, which suggests a hydrophobic capacity. The oil absorption rate of the fabric can reach 10.34, demonstrating excellent oil/water separation performance. The successful preparation of PLA/PBE micro-nanofiber fabrics using our new method paves the way for the large-scale production of promising candidates for high-efficacy oil/water separation applications.