Elastic Bio-based Polyurethane Nanofibrous Membrane with Robust Waterproof and Breathable Properties

Elastic bio-based waterproof and breathable membranes(EBWBMs) allow the passage of water vapor effectively and resist the penetration of liquid water,making it ideal for use under extreme conditions.In this study,we used a facile strategy to design the bio-based polyurethane(PU) nanofibrous membranes with the nanoscale porous structure to provide the membranes with high waterproof and breathable performances.The optimization of nanofibrous membrane formation was accomplished by controlling the relative ambient humidity to modulate the cooperating effects of charge dissipation and non-solvent-induced phase separation.The obtained EBWBMs showed multiple functional properties,with a hydrostatic pressure of 86.41 kPa and a water vapor transmission(WVT) rate of 10.1 kg·m^(-2)·d^(-1).After 1 000 cycles of stretching at 40% strain,the EBWBMs retained over 59% of the original maximum stress and exhibited an ideal elasticity recovery ratio of 85%.Besides,even after 80% deformation,the EBWBMs still maintained a hydrostatic pressure of 30.65 kPa and a WVT rate of 13.6 kg·m^(-2)·d^(-1),suggesting that bio-based PU nanofibrous membranes could be used for protection under extreme conditions.

Breathable Electronic Skins for Daily Physiological Signal Monitoring

With the aging of society and the increase in people’s concern for personal health,long-term physiological signal monitoring in daily life is in demand.In recent years,electronic skin(e-skin)for daily health monitoring applications has achieved rapid development due to its advantages in high-quality physiological signals monitoring and suitability for system integrations.Among them,the breathable e-skin has developed rapidly in recent years because it adapts to the long-term and high-comfort wear requirements of monitoring physiological signals in daily life.In this review,the recent achievements of breathable e-skins for daily physiological monitoring are systematically introduced and discussed.By dividing them into breathable e-skin electrodes,breathable e-skin sensors,and breathable e-skin systems,we sort out their design ideas,manufacturing processes,performances,and applications and show their advantages in long-term physiological signal monitoring in daily life.In addition,the development directions and challenges of the breathable e-skin are discussed and prospected.

Breathable,antifreezing,mechanically skin-like hydrogel textile wound dressings with dual antibacterial mechanisms

Hydrogels are emerging as the most promising dressings due to their excellent biocompatibility,extracellular matrix mimicking structure,and drug loading ability.However,existing hydrogel dressings exhibit limited breathability,poor environmental adaptability,potential drug resistance,and limited drug options,which extremely restrict their therapeutic effect and working scenarios.Here,the current research introduces the first paradigm of hydrogel textile dressings based on novel gelatin glycerin hydrogel(glyhydrogel)fibers fabricated by the Hofmeister effect based wet spinning.Benefiting from the unique knitted structure,the textile dressing features excellent breathability(1800 times that of the commercially available 3 M dressing)and stretchability(535.51±38.66%).Furthermore,the glyhydrogel textile dressing can also withstand the extreme temperature of-80℃,showing the potential for application in subzero environments.Moreover,the introduction of glycerin endows the textile dressing with remarkable antibacterial property and expands the selection of loaded drugs(e.g.,clindamycin).The prepared glyhydrogel textile dressing shows an excellent infected wound healing effect with a complete rat skin closure within 14 days.All these functions have not been achievable by traditional hydrogel dressings and provide a new approach for the development of hydrogel dressings.

Stretchable, self‐healable, and breathable biomimetic iontronics with superior humidity‐sensing performance for wireless respiration monitoring

Stretchable,self‐healing,and breathable skin‐biomimetic‐sensing iontronics play an important role in human physiological signal monitoring and human–computer interaction.However,previous studies have focused on the mimicking of skin tactile sensing(pressure,strain,and temperature),and the development of more functionalities is necessary.To this end,a superior humidity‐sensitive ionic skin is developed based on a self‐healing,stretchable,breathable,and biocompatible polyvinyl alcohol–cellulose nanofibers organohydrogel film,showing a pronounced thickness‐dependent humidity‐sensing performance.The as‐prepared 62.47‐μm‐thick organohydrogel film exhibits a high response(25,000%)to 98%RH,excellent repeatability,and long‐term stability(120 days).Moreover,this ionic skin has excellent resistance to large mechanical deformation and damage,and the worn‐out material can still retain its humidity‐sensing capabilities after self‐repair.Humidity‐sensing mechanism studies show that the induced response is mainly related to the increase of proton mobility and interfacial charge transport efficiency after water adsorption.The superior humidity responsiveness is attributed to the reduced thickness and the increased specific surface area of the organohydrogel film,allowing real‐time recording of physiological signals.Notably,by combining with a self‐designed printed circuit board,a continuous and wireless respiration monitoring system is developed,presenting its great potential in wearable and biomedical electronics.

Stretchable,breathable,and washable epidermal electrodes based on microfoam reinforced ultrathin conductive nanocomposites

Stretchable epidermal electronics allow conformal interactions with the human body for emerging applications in wearable health monitoring and therapy.Stretchable devices are commonly constructed on submillimeter-thick elastomer substrates with limited moisture permeability,thereby leading to unpleasant sensations during long-term attachment.Although the ultrathin elastomer membrane may address this problem,the mechanical robustness is essentially lost for direct manipulations and repetitive uses.Here,we report a stretchable,breathable,and washable epidermal electrode of microfoam reinforced ultrathin conductive nanocomposite(MRUCN).The new architecture involves ultrathin conductive silver nanowire nanocomposite features supported on a porous elastomeric microfoam substrate,which exhibits high moisture permeability for pleasant perceptions during epidermal applications.As-prepared epidermal electrodes show excellent electronic conductivity(8440 S·cm^(-1)),high feature resolution(~50μm),decent stretchability,and excellent durability.In addition,the MRUCN retains stable electrical properties during washing to meet the hygiene requirements for repetitive uses.The successful implementation in an integrated electronic patch demonstrates the practical suitability of MRUCN for a broad range of epidermal electronic devices and systems.

An ultra-thin piezoelectric nanogenerator with breathable,superhydrophobic,and antibacterial properties for human motion monitoring

Piezoelectric nanogenerators(PENGs)are promising for harvesting renewable and abundant mechanical energy with high efficiency.Up to now,published research studies have mainly focused on increasing the sensitivity and output of PENGs.The technical challenges in relation to practicability,comfort,and antibacterial performance,which are critically important for wearable applications,have not been well addressed.To overcome the limitations,we developed an all-nanofiber PENG(ANF-PENG)with a sandwich structure,in which the middle poly(vinylidene fluoride-co-hexafluoropropylene(P(VDF-HFP))/ZnO electrospun nanofibers serve as the piezoelectric layer,and the above and below electrostatic direct-writing P(VDF-HFP)/ZnO nanofiber membranes with a 110 nm Ag layer on one side that was plated by vacuum coating technique serve as the electrode layer.As the ANF-PENG only has 91μm thick and does not need further encapsulating,it has a high air permeability of 24.97 mm/s.ZnO nanoparticles in ANF-PENG not only improve the piezoelectric output,but also have antibacterial function(over 98%).The multifunctional ANF-PENG demonstrates good sensitivity to human motion and can harvest mechanical energy,indicating great potential applications in flexible self-powered electronic wearables and body health monitoring.

Recent advances in breathable electronics

The successful implementation of bioelectronic devices attached to living organism hinges on a number of material and device characteristics,including not only electrical and mechanical performances to gather physiological signals from living organism thus enabling status monitoring,but also permeability or breathability for gas/nutrient exchange between living organisms and surroundings to ensure minimum perturbation of the intrinsic biological function.However,most bioelectronic devices built on planar polymeric substrates,such as polydimethylsiloxane(PDMS),polyurethane(PU),and polyimide(PI),lack efficient gas permeability,which may hinder the emission of volatile compounds from the surface of living organism,affecting the natural metabolism and reducing the comfort of wearing.Thus,achieving permeability or breathability in bioelectronic devices is a significant challenge.Currently,the devices made of gas-permeable materials with porous structures,that combine electronic components with daily garments,such as fibric and textile,offer exciting opportunities for breathable electronics.In this review,several types of gas-permeable materials with their synthesis and processing routes are outlines.Then,two methods for measuring water vapor transmission rate of materials are discussed in depth.Finally,recent progress in the use of gaspermeable materials for the applications of plant-and skin-attached electronics is summarized systematically.

A waterproof and breathable Cotton/rGO/CNT composite for constructing a layer-by-layer structured multifunctional flexible sensor

Developing a cotton fabric sensing layer with good waterproofness and breathability via a low-cost and eco-friendly method is increasingly important for the construction of comfortable and wearable electronic devices.Herein,a waterproof and breathable cotton fabric composite decorated by reduced graphene oxide(rGO)and carbon nanotube(CNT),Cotton/rGO/CNT,is reported by a facile solution infiltration method,and we adopt such Cotton/rGO/CNT composite to develop a layer-by-layer structured multifunctional flexible sensor,enabling the high-sensitivity detection of pressure and temperature stimulus.Particularly,the multifunctional flexible sensor exhibits a high response toward tiny pressure,demonstrating salient superiority in the continuous and reliable monitoring of human physiological information.Concerning temperature sensing,a good linear response for the temperatures ranging from 28 to 40℃ is achieved by the multifunctional flexible sensor and gives rise to be successfully applied to the non-contact real-time monitoring of human respiration signal.Finally,an array consisting of multifunctional flexible sensors further demonstrates its feasibility in perceiving and mapping the pressure and temperature information of contact objects.This work provides a feasible strategy for designing cotton-based sensing layers that can effectively resist liquid water penetration and allow water vapor transmission,and offers reasonable insight for constructing comfort and multifunctional wearable electronics.

Breathable Kirigami‑Shaped Ionotronic e‑Textile with Touch/Strain Sensing for Friendly Epidermal Electronics

Flexible ionotronic devices have great potential to revolutionize epidermal electronics.However,the lack of breathability in most ionotronic devices is a significance barrier to practical application.Herein,a breathable kirigami-shaped ionotronic e-textile with two functions of sensing(touch and strain)is designed,by integrating silk fabric and kirigami-shaped ionic hydrogel.The kirigami-shaped ionic hydrogel,combined with fluffy silk fabric,allows the ionotronic e-textile to achieve excellent breathability and comfortability.Furthermore,the fabricated ionotronic e-textile can precisely perform the function of touch sensing and strain perception.For touch-sensing,the ionotronic e-textile can detect the position of finger touching point with a fast response time(3 ms)based on the interruption of the ion field.For strain sensing,large workable strain range(>100%),inconspicuous drift(<0.78%)and long-term stability(>10,000 cycles)is demonstrated.On the proof of concept,a fabric keyboard and game controlling sleeve have been designed to display touch and strain sensing functions.The ionotronic e-textile break through the bottlenecks of traditional wearable ionotronic devices,suggesting a great promising application in future wearable epidermal electronics.

A novel breathable flexible metallized fabric for wearable heating device with flame-retardant and antibacterial properties

Currently,there is an imperative demand for developing a novel flexible heater with high adhesion,breathability,and extreme condition resistance,such as ultra-high temperatures and even fire.Herein,a high-adhesion,flame-retardancy,and anti-bacteria copper nanoparticles networks/nylon 6 woven fabric(CNNs/NWF)wearable heater with a“sandwich-like”structure has been designed and fabricated based on phatic acid/aminopropyltriethoxysilane(PA/APTES)hybrid coating.On the one hand,the CNNs/NWF wearable heater exhibited superb electrothermal behavior working at a peak temperature of 208.8℃powered with 2.0 V,better than that of wearable heaters in the recently reported literature.On the other hand,the vertical burning test showed that the heater possesses splendid flame retardancy.Furthermore,the PA/APTES coating could deposit a nanoscale porous protective film on the surface of CNNs/NWF,which imparts the heater with relatively excellent oxidation resistance and breathability.In addition,the antibacterial efficiency against Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)still reached100%after 50 times of standard washing and being electrified at 2.0 V for 5 min,keeping humans away from the threat of bacterial infections.We think that the heater in this research could be extended to wearable heating devices.

Effects of Soft Monomers on the Water Resistance and Moisture Permeability of Hydrophilic Polyurethane

Six groups of segmented polyurethanes with amorphous soft segment domains based on mixed hydrophobic polyester and hydrophilic polyether soft monomers were prepared from 4, 4′ diphenylmethane diisocyanate （MDI）, polybutylene adipate glycol 2000 （PBA2000）, polytetramethylene glycol 1000 （PTMG1000） and polyethylene glycol 1000 （PEG1000） with 1,4-butanediol （BDO） as the chain extender. Furthermore, the representative properties of the hydrophilic polyurethanes, moisture permeability and water resistance, were investigated. The results show that the chemical structure, molecular weight and concentration of soft monomers have remarkable effects on the main application properties of hydrophilic polyurethane. The important factors in diffusion are the content of hydrophilic ether bond and the mobility of hydrophilic chain in the soft phase, which is represented with a good approximation by the average mean molecular weight of soft segment. On the contrary, the functional properties of the hydrophilic polyurethane are almost not affected by its hard segment.

Use of the Appropriate Fabric for Cloth Face Mask: A Necessity in the Fight against COVID-19

The outbreak of coronavirus disease (COVID-19) has created a global health crisis that has had a deep impact on the way we perceive our world and our everyday lives. The call for the wearing of face masks as one of the ways of curbing the disease has resulted in the proliferation of cloth face masks on our markets. In the desperation to cash in on the season and make money at all costs, some manufacturers use inferior fabrics to produce face masks. Some of these fabrics do not meet the basic performance requirements of cloth face masks. This study was therefore carried out to research into the appropriate fabrics that will be suitable for the production of cloth face masks in terms of comfort, breathability and protection. To do this, 1225 participants were conveniently drawn for the study. The main research instrument employed for the study was the survey approach in which well-structured questionnaires were administered to solicit information from the participants. To determine the reliability and validity of data, the Cronbach’s Alpha test was conducted. Data were analyzed using the Stata statistical software to perform a multinomial logistic regression to estimate Odds Ratios (ORs) with 95% CIs. A multinomial logit model was constructed to determine the nominal variables. A major finding of the study was that people’s choice of fabric for cloth face masks is determined to a larger extent by their professions. The study also revealed that cotton, silk and linen possess good properties for the production of cloth face masks. Based on the findings, the study concludes that cloth face masks made from two-layered fabrics or three-layered fabrics are the best in terms of comfort and full protection of the wearer. It is recommended that the outer layer should be made from cotton and the inner layer made from linen, cotton-polyester blend or silk.

具有增强一致性和透气性的无基底超薄表皮生物电极用于长期生理监测

开发耐用且可靠的生物电极,用以采集高质量的生物电信号,已成为人体生理状态监测和人机交互领域的关键技术.然而,现有的生物电极多基于传统弹性基底,这导致了机械性能不匹配和低渗透性等问题,并且缺乏与生物皮肤类似的多方面属性和必要的协同特性.本研究中,我们报道了一种新型的基于自支撑导电全聚合物薄膜的超薄表皮生物电极(ASU-EBE).该电极将超一致性、优异的拉伸性和透气性集成于一体,展现了约475 S cm^(-1)的高导电性,约48%的出色拉伸性,与生物组织界面的超一致性以及优异的透气性.该电极的电子和机械性能得到提升,这归功于在PEDOT:PSS中引入水溶性聚氧化乙烯,以调节分子间π-π堆积距离,并促进纳米纤维结构的形成.因此,ASU-EBE在与皮肤接触时的阻抗远低于标准凝胶电极,使其成为复杂日常环境下长期医疗监测的理想选择.

Water Responsive Fabrics with Artificial Leaf Stomata

Due to fiber swelling,textile fabrics containing hygroscopic fibers tend to decrease pore size under wet or increasing humid-ity and moisture conditions,the reverse being true.Nevertheless,for personal thermal regulation and comfort,the opposite is desirable,namely,increasing the fabric pore size under increasing humid and sweating conditions for enhanced ventila-tion and cooling,and a decreased pore size under cold and dry conditions for heat retention.This paper describes a novel approach to create such an unconventional fabric by emulating the structure of the plant leaf stomata by designing a water responsive polymer system in which the fabric pores increase in size when wet and decrease in size when dry.The new fabric increases its moisture permeability over 50%under wet conditions.Such a water responsive fabric can find various applications including smart functional clothing and sportswear.

Novel liquid scintillator radon detector

Purpose Radon is a noble gas,which endangers our health.The liquid scintillator is one of the detector materials used to measure radon in the environment.But there are challenges in measuring radon using a liquid scintillator,such as independent manual operation and long measurement periods.Methods and Results We propose a liquid scintillator detector for the rapid measurement of radon,which is composed of a breathable liquid scintillator probe and photomultiplier tube.Cascade decay recognition and pulse shape discrimination(PSD)were used to select radon events.241 Am4(α)and 90Sr(β)source calibration was used to optimize the PSDfigure of merit of the liquid scintillator,and a 232Th(220Rn)diffusion source was used to verify the function of this novel detector for measuring radon.Conclusion The detector had an integrated design for sampling and measurement,which simplified the measurement steps.Thus,this novel liquid scintillator detector demonstrated promise for use in radon-detection systems.

Electrospun Nanofibrous Materials for Wound Healing

Wound dressing materials which are capable of meeting the demands of accelerating wound closure and promoting wound healing process have being highly desired.Electrospun nanofibrous materials show great application potentials for wound healing owing to relatively large surface area,better mimicry of native extracellular matrix,adjustable waterproofness and breathability,and programmable drug delivery process.In this review article,we begin with a discussion of wound healing process and current commercial wound dressing materials.Then,we emphasize on electrospun nanofibrous materials for wound dressing,covering the efforts for controlling fiber alignment and morphology,constructing 3D scaffolds,developing waterproof-breathable membrane,governing drug delivery performance,and regulating stem cell behavior.Finally,we finish with challenges and future prospects of electrospun nanofibrous materials for wound dressings.