基于MXenes的功能纤维的制备及其在智能可穿戴领域的应用

在电子信息和物联网技术的推动下,人类对可穿戴电子器件和智能织物的需求愈发突出,功能纤维作为智能可穿戴设备的重要载体,近年来获得快速发展。功能纤维的性能很大程度上取决于纤维的基础构筑单元。过渡金属碳/氮化物(MXenes)作为一种新兴的二维材料,凭借其高电导率、优异的可加工性能、可调节的表面特性以及出色的机械强度等优点,受到了极大的关注,也逐渐成为构筑功能纤维的重要单元。本文将主要综述MXenes的湿化学、熔融盐、无氟试剂刻蚀等方法和力学、电学、光学和化学稳定性等性能,阐述基于该材料制备的功能纤维在传感、储能以及其他智能领域的应用,最后讨论了基于MXenes材料的功能纤维的未来应用前景和技术挑战。

High-Performance Ionic Thermoelectric Supercapacitor for Integrated Energy Conversion-Storage

Converting low-grade waste heat into usable electricity and storing it simultaneously requires a new technology that realize the directional migration of electrons or ions under temperature difference and enrichment on the electrodes.Although the urgent demand of energy conversion-storage(ECS)has emerged in the field of wearable electronic,achieving the integrated bi-functional device remains challenge due to the different mechanisms of electrical transportation and storage.Here,we report an ionic thermoelectric supercapacitor that relies on the synergistic functions of thermoelectricity and supercapacitor in the thermoelectric ionogel electrolyte and high-performance hydrogel electrodes to enhance the ECS performance under a thermal gradient.The thermoelectric electrolyte is composed of polyacrylamide hydrogel and sodium carboxymethyl cellulose(PMSC),possessing cross-linked network with excellent cation selectivity,while the ionic thermoelectric properties are further improved in the presence of NaCl.The corresponding Seebeck coefficient and ionic conductivity of the NaCl–PMSC electrolyte reach 17.1 mV K^(-1)and 26.8 mS cm^(-1),respectively.Owing to good stretchability of both gel-based electrolyte and electrode,the fullstretchable integrated ECS device,termed ionic thermoelectric supercapacitor,presents promising thermal-charge storage capability(~1.3 mC,ΔT≈10 K),thus holds promise for wearable energy harvesting.

Advanced Functional Fiber and Smart Textile

The research and applications of fiber materials are directly related to the daily life of social populace and the development of relevant revolutionary manufacturing industry.However,the conventional fibers and fiber products can no longer meet the requirements of automation and intellectualization in modern society,as well as people’s consumption needs in pursuit of smart,avant-grade,fashion and distinctiveness.The advanced fiber-shaped electronics with most desired designability and integration features have been explored and developed intensively during the last few years.The advanced fiber-based products such as wearable electronics and smart clothing can be employed as the second skin to enhance information exchange between humans and the external environment.In this review,the significant progress on flexible fiber-shaped multifunctional devices,including fiber-based energy harvesting devices,energy storage devices,chromatic devices,and actuators are discussed.Particularly,the fabrication procedures and application characteristics of multifunctional fiber devices such as fiber-shaped solar cells,lithium-ion batteries,actuators and electrochromic fibers are introduced in detail.Finally,we provide our perspectives on the challenges and future development of functional fiber-shaped devices.

Stretchable electrothermochromic fibers based on hierarchical porous structures with electrically conductive dual-pathways

Stretchable color-changing fibers are urgently demanded for smart textiles/clothing due to their perfect implantability,permeability of vapor and heat,and flexibility/stretchability.Herein,stretchable electrothermochromic fibers were fabricated with unconventional stretchable conductive fibers as core layers and thermochromic coatings as shell layers.In the stretchable conductive fibers,hierarchical porous structures with percolative one-dimensional(1 D)conductive networks were constructed through phase inversion of carbon nanotube/polyurethane(CNT/PU)solutions.With the deposition of silver nanoparticles(AgN Ps)on the surface of micro-pores,electrically conductive dual-pathways consisting of0 D AgN Ps and 1 D CNTs were formed to significantly enhance the electric conductivity and thus improve the electrothermal performance of the fibers.More importantly,because of the connective CNTs and AgN Ps,such dual-pathways ensured the electron transport under the stretching state,preventing the sharp decay of conductivity and electrothermal performance.Through the continuous wet-spinning method,the stretchable conductive fibers can be easily obtained with the length up to several meters.At last,stretchable electrothermochromic fibers were prepared with two color-changing modes and implanted into textile perfectly,advancing their applications in wearable display and military adaptive camouflage of smart clothing.

Independent dual-responsive Janus chromic fibers

Daily exposure under solar ultraviolet(UV)and infrared(IR)is prone to cause skin cancer and photoaging.Real-time monitoring of the environmental UV index and IR radiation temperature during outdoor activities can enhance awareness and strengthen personal protection.It is a challenge to design flexible,wearable devices(with measurement capabilities)that can be integrated with apparels.Here,microfluidic spinning technology(MST)was used for the continuous and large-scale fabrication of eco-friendly coresheath Janus fibers with a well-defined axially symmetric Janus core.One side of the core was sensitive to UV light and the opposite was sensitive to IR radiation.Textiles woven with Janus fibers showed excellent independent reversible color responses to dual-wavelength stimulation.Such textiles switched among four colors under UV and IR irradiation,both individually and in combination.The color gradient of the textiles changed significantly with increasing UV intensity(UV index).After 60 cycles of UV/IR stimulation and 50 washes,the change rate of the comprehensive chromatic aberration(ΔE_(ab)^(*))of the textiles under different conditions was only 0.42%-4.71%.This was attributed to the unique structure of the fibers.The three-line striped textiles demonstrated the potential of the fibers to be used as wearable energy-free realtime visual monitors of the UV index and IR radiation temperature.

Wearable Fiber‑Based Supercapacitors Enabled by Additive‑Free Aqueous MXene Inks for Self‑Powering Healthcare Sensors

Wearable fiber-based electronics have found diverse applications including energy storage,healthcare or thermal management,etc.In particular,additive-free aqueous inks play significant roles in fabrication of wearable fiber-based devices,owning to their nontoxic nature and ease of manufacturing.Herein,wearable carbon fiber-based asymmetric supercapacitors(WASSC)are developed based on additive-free aqueous MXene inks,for self-powering healthcare sensors.The sediments of MXene without further modification are used as inks.Furthermore,combined with additive-free aqueous MXene/polyaniline(MP)inks,WASSC,with a wide voltage window and high capacitance is developed for practical energy supply.Impressively,WASSC has been successfully utilized to power wearable pressure sensors that could monitor motions and pulse signals.This wearable self-powered monitoring system on can accurately monitor the human motions,pronunciation,swallow or wrist pulse,without using the rigid batteries.This advantage realizes a great potential in simple and cost effective monitoring of human health and activities.Besides,self-powered system enables waste recycling of MXene and provides an effective approach for designing wearable and fiber-based self-powered sensors.

Dielectrophoretic Assembly of Carbon Nanotube Chains in Aqueous Solution

Carbon nanotubes(CNTs)have generated remarkable interests in a wide range of research fields due to their excellent electri-cal properties.However,achieving the CNTs arrangement with high quality in a short time remains a challenge.Herein we studied the in-situ assembly of CNTs based on macroscopic dielectrophoresis by using a centimeter scale electrode,which overcome the limitation of small size in traditional method for manipulating nanoparticles.Ordered CNTs chains could be obtained under the action of alternating current dielectrophoresis by optimizing the voltage and frequency.Besides,the ordered chains were able to restore immediately upon powering up after being damaged.Furthermore,a CNTs chain was prepared for conducting the wet circuit and powering a LED,and different conductive patterns on the non-woven fabric were achieved by controlling the position of the electrodes in wet environment.