Showing papers by "Kin-tak Lau published in 2022"
TL;DR: In this paper , a structured electrospun membrane with controllable structures of microbeads and fine nanofibers was constructed and the deformation of diverse polymeric solution droplets in the electrospinning process under varying electric fields was simulated by molecular dynamic simulation.
Abstract: Electrospinning is a feasible technology to fabricate nanomaterials. However, the preparation of nanomaterials with controllable structures of microbeads and fine nanofibers is still a challenge, which hinders widespread applications of electrospun products. Herein, inspired by the micro/nanostructures of lotus leaves, we constructed a structured electrospun membrane with excellent comprehensive properties. First, micro/nanostructures of membranes with adjustable microbeads and nanofibers were fabricated on a large scale and quantitatively analyzed based on the controlling preparation, and their performances were systematically evaluated. The deformation of diverse polymeric solution droplets in the electrospinning process under varying electric fields was then simulated by molecular dynamic simulation. Finally, novel fibrous membranes with structured sublayers and controllable morphologies were designed, prepared, and compared. The achieved structured membranes demonstrate a high water vapor transmission rate (WVTR) > 17.5 kg/(m2 day), a good air permeability (AP) > 5 mL/s, a high water contact angle (WCA) up to 151°, and a high hydrostatic pressure of 623 mbar. The disclosed science and technology in this article can provide a feasible method to not only adjust micro/nanostructure fibers but also to design secondary multilayer structures. This research is believed to assist in promoting the diversified development of advanced fibrous membranes and intelligent protection.
7 citations
TL;DR: In this article , a bioinspired dry Janus all-natural facial mask (J-AFM) has been developed by a simple green-solvent-based electrospinning method.
Abstract: Facial masks cause huge pollution and resource waste, posing a serious threat to the ecological environment and human health. Inspired by lotus leaves, a bioinspired dry Janus all-natural facial mask (J-AFM) has been developed by a simple green-solvent-based electrospinning method. The dry J-AFM can drive water from the outside directionally to dissolve the inner nanofiber layer of nutrients quickly, while keeping the outside dry and delaying moisture evaporation. Compared with commercial wet facial masks, the dry J-AFM can reduce the total weight by 87 and 100% to avoid plastic pollution by using paper-based packaging. In addition, the waste of water and active nutrients can be reduced by 100%. The dry J-AFM with good antibacterial activity and biocytocompatibility can not only avoid the use of preservatives but also shows an obvious skincare effect. This research can trigger the reform of ecofriendly facial masks and guide the chemical industry toward sustainable and healthy development.
6 citations
TL;DR: In this article , the authors proposed and demonstrated the concept of dynamically tunable thermochromic graphene metamaterials (TGMs), which can achieve continuous color tunability (380-800 nm) with fast (<100 ms) response times.
Abstract: Thermochromic materials have been widely applied in energy-efficient buildings, aerospace, textiles, and sensors. Conventional thermochromic materials rely on material phase or structure changes upon thermal stimuli, which only enable a few colors, greatly limiting their applicability. Here, we propose and demonstrate the concept of dynamically tunable thermochromic graphene metamaterials (TGMs), which can achieve continuous color tunability (380-800 nm) with fast (<100 ms) response times. The TGMs are composed of an ultrathin graphene oxide (GO) film on a flexible metal substrate. We demonstrated that external thermal energy can dynamically adjust the water contents in the GO film to manipulate the color of TGMs. An impressive thermochromic sensitivity of 1.11 nm/°C covering a large percentage of the color space has been achieved. Prototype applications for a cup and smartphone have been demonstrated. The reversible TGMs promise great potential for practical applications of temperature sensing in optoelectronic devices, environmental monitoring, and dynamic color modulation.
3 citations
TL;DR: In this paper , the key designs and strategies to reconcile the trade-off between mechanical properties and energy storage performances of structural dielectric capacitors, a typical type of structural energy storage composites, are highlighted.
Abstract: Structural energy storage composites, which combine energy storage capability with load-carrying function, are receiving increasing attention for potential use in portable electronics, electric vehicles, and aircraft structures to store electrical energy in replace of traditional electrochemical energy storage devices. The integration of energy storage ability into mechanically strong carbon fibre reinforced polymer composite is promising in reducing the weight and volume while providing additional functions, ultimately leading to energy-efficient systems. In this review, the key designs and strategies to reconcile the trade-off between mechanical properties and energy storage performances of structural dielectric capacitors, a typical type of structural energy storage composites, are highlighted. Opportunities and challenges are also discussed for the further development of structural energy storage composites for aviation applications.