Cooling is pervasive in modern society and contributes significantly to global energy use. A hierarchical-morphology metafabric has been recently reported to show efficient passive daytime radiative cooling ability and may be also easily scaled up by industrial textile manufacturing technology. The above study represents an important advance in personal thermal management through the use of intelligent garments.
Shape memory polymer (SMP) is a kind of material that can sense and respond to the changes of the external environment, and its behavior is similar to the intelligent reflection of life. Electrospinning, as a versatile and feasible technique, has been used to prepare shape memory polymer fibers (SMPFs) and expand their structures. SMPFs show some advanced features and functions in many fields. In this review, we give a comprehensive overview of SMPFs, including materials, fabrication methods, structures, multifunction, and applications. Firstly, the mechanism and characteristics of SMP are introduced. We then discuss the electrospinning method to form various microstructures, like non-woven fibers, core/shell fibers, hollow fibers and oriented fibers. Afterward, the multiple functions of SMPFs are discussed, such as multi-shape memory effect, reversible shape memory effect and remote actuation of composites. We also focus on some typical applications of SMPFs, including biomedical scaffolds, drug carriers, self-healing, smart textiles and sensors, as well as energy harvesting devices. At the end, the challenges and future development directions of SMPFs are proposed.
Research in neuroscience and neuroengineering has attracted tremendous interest in the past decades. However, the complexity of the brain tissue, in terms of its structural, chemical, mechanical, and optical properties, makes the interrogation of biophysical and biochemical signals within the brain of living animals extremely challenging. As a viable and versatile tool for brain studies, optical fiber based technologies have provided exceptional opportunities to unravel the mysteries of the brain and open the door for clinical applications in the treatment, diagnosis, and prevention of neurological diseases. Typically, optical fibers with diameters from 10 to 1000 μm are capable of guiding and delivering light to deep levels of the living tissue. Moreover, small dimensions of such devices along with their flexibility and light weight paved the way for understanding the complex behaviours of living and freely moving mammals. This article provides a review of the emerging applications of optical fibers in neuroscience, specifically in the mammalian brain. Representative utilities, including optogenetics, fluorescence sensing, drug administration and phototherapy, are highlighted. We also discuss other biological applications of such implantable fibers, which may provide insights into the future study of brain. It is envisioned that these and other optical fiber based techniques offer a powerful platform for multi-functional neural activity sensing and modulation.
As a promising energy storage device, sodium-ion batteries (SIBs) have received continuous attention due to their low-cost and environmental friendliness. However, the sluggish kinetics of Na ion usually makes SIBs hard to realize desirable electrochemical performance when compared to lithium-ion batteries (LIBs). The key to addressing this issue is to build up nanostructured materials which enable fast Na-ion insertion/extraction. One-dimensional (1D) nanocarbons have been considered as both the anode and the matrix to support active materials for SIB electrodes owing to their high electronic conductivity and excellent mechanical property. Because of their large surface areas and short ion/electron diffusion path, the synthesized electrodes can show good rate performance and cyclic stability during the charge/discharge processes. Electrospinning is a simple synthetic technology, featuring inexpensiveness, easy operation and scalable production, and has been largely used to fabricate 1D nanostructured composites. In this review, we first give a simple description of the electrospinning principle and its capability to construct desired nanostructures with different compositions. Then, we discuss recent developments of carbon-based hybrids with desired structural and compositional characteristics as the electrodes by electrospinning engineering for SIBs. Finally, we identify future research directions to realize more breakthroughs on electrospun electrodes for SIBs.
Nanowires (NWs) with ultrahigh aspect ratio are good one-dimensional (1D) nano scaffolds for building functional aerogels. However, challenges still remain in exploring methods to prepare shape designable NW aerogels with high quality, and to reveal multi functions in a single NW aerogel monolith. Here, we report a general camphene freeze-drying method for preparation of various inorganic NW aerogels (e.g, Cu, hydroxylapatite, MnO2 and MnOOH NW aerogels), 2D graphene oxide nanosheet aerogels, organic polymer aerogels of polystyrene (post-synthesis) and resin (in situ polymerization) aerogels, which can be freely shaped in the frozen monolith stage. The as prepared aerogels have even distributed porosity and smooth surface. Also camphene is cheap and can be effectively recycling collected for reuse. For the Cu NW aerogel with even porosity and low density of 20 mg cm−3, multifunctional pressure/gas/photo-sensing was demonstrated. A high pressure sensitivity of 1.7 kPa−1 was achieved.
Metronidazole (MTZ) loaded Eudragit S-100 (ES-100) nonwoven nanofibrous mats were successfully electrospun and evaluated for intestinal drug delivery. MTZ was varied in the range of 1–15% (w/w) in ES-100 nanofibrous mats, the morphological characterization of nanofibrous mats was carried out using FE-SEM and the average diameter of nanofiber was found in the range 150–600 nm. WAXD and DSC demonstrated the amorphous nature of MTZ in ES-100 nanofibrous mats. Their contact angle analysis confirmed the hydrophobic nature. The mechanical strength of ES-100 nanofibrous mats decreased with increasing MTZ concentration. The drug release profiles showed 74% MTZ release from ES-100d within 2 h at pH 6.8 which is the colonic environment. Antibacterial activities against gram-positive bacteria (Staphylococcus aureus) and gram-negative bacteria (Escherichia coli) showed that the ES-100 nanofibrous mats loaded with MTZ exhibited good activity.
In this work, the silk fibroin/cellulose blend nanofibrous membranes modified with sodium-3-sulfobenzoate (S-SCBNM) were fabricated by electrospinning technique for lysozyme adsorption. The morphology and structure of membranes was observed. The effect of sulfate contents, pH values and concentration of lysozyme on adsorption performance were studied, respectively. The reuse capacity was evaluated. The results showed that the resultant S-SCBNM exhibited integrated properties of ultrathin fiber diameter (148 nm), fast adsorption equilibrium, excellent adsorption performance (636 mg g−1) and good reversibility. We envision that this new class of green and natural blend membranes is particularly promising for the development of proteins separation.
Ionogels with high transparency, stretchability and self-healing capability show great potential for wearable electronics. Here, a kind of highly transparent, stretchable and self-healable ionogels are designed using double physical cross-linking including hydrogen bonding and dipole–dipole interaction. Owing to the dynamic and reversible nature of the ion–dipole interaction and hydrogen bonds of polymeric chains, the ionogel possesses good self-healing capability. The multifunctional sensors for strain and temperature are fabricated based on ionogel. The ionogel can serve as strain sensor that exhibited high sensitivity [gauge factor (GF) = 3.06] and durability (1000 cycles) to a wide range of strains (0–300%). Meanwhile, the ionogel shows rapid response to temperature, due to the temperature dependence of its ionic conductivity. Furthermore, the ionogel fibers with excellent antifreezing (− 20 °C) capability are fabricated, and the fibers show the good sensing performance to human motions and temperature. Importantly, the antifreezing ionogel-based triboelectric nanogenerator (ITENG) is assembled for efficient energy harvesting. The ITENG shows a short circuit current (I SC) of 6.1 μA, open circuit voltage (V OC) of 115 V, and instantaneous peak power density of 334 mW m−2. This work provides a new strategy to design ionogels for the advancement of wearable electronics.
The separator with excellent mechanical and thermal properties are highly required for lithium ion batteries (LIBs). Therefore, it is crucial to develop novel nanofibrous membranes with enhanced mechanical strength and thermal stability. In this work, the fluorinated polyimide (FPI) was synthesized and blended with polyvinylidene fluoride (PVDF) to fabricate composite nanofibrous membranes (CNMs) via electrospinning method. Benefiting from the introduction of aromatic FPI, the prepared PVDF/FPI nanofibrous membranes were endowed with enhanced mechanical strength and thermal stability. When the FPI content increased from 0 to 30 wt%, the tensile strength of composite nanofibrous membranes enhanced from 1.57 to 2.30 MPa. Moreover, there are almost no dimensional shrinkage for the CNM-30 containing 30 wt% FPI after heat treatment at 160 °C for 1 h. Furthermore, the prepared CNMs show improved electrochemical performances in comparison with neat PVDF and commercial Celgard membranes. The electrolyte uptake and ionic conductivity of the CNMs could reach to 522.4% and 1.14 ms·cm−1, respectively. The prepared CNMs could provide an innovative and promising approach for the development and design of high-performance separators.
Pathogenic bacteria can proliferate rapidly on porous fabrics to form bacterial plaques/biofilms, resulting in potential sources of cross-transmissions of diseases and increasing cross-infection in public environments. Many works on antibacterial modification of cotton fabrics have been reported, while very few works were reported to endow poly(ethylene terephthalate) (PET) fabrics with non-leaching antibacterial function without compromising their innate physicochemical properties though PET is the most widely used fabric. Therefore, it is urgent to impart the PET fabrics with non-leaching antibacterial activity. Herein, a novel N-halamine compound, 1-chloro-3-benzophenone-5,5-dimethylhydantoin (Cl-BPDMH), was developed to be covalently bonded onto PET fabrics, rendering non-leaching antibacterial activity while negligible cytotoxicity based on contact-killing principle. Bacterial was easily adhered to Cl-BPDMH finished PET fabrics, and then it was inactivated quickly within 10 s. Furthermore, the breaking strength, breaking elongation, tearing strength, water vapor permeability, air permeability and whiteness of Cl-BPDMH finished PET fabrics were improved obviously compared to raw PET fabrics. Hence, this work developed a facile approach to fabricate multifunctional synthetic textiles to render outstanding and rapid bactericidal activity without compromising their physicochemical properties and biocompatibility.