Large-scale blow spinning of heat-resistant nanofibrous air filters

Particulate matter(PM)pollution has become a serious problem worldwide and various kinds of nanofibrous filters aiming to solve the problem have been developed.It is urgent to remove PM from high-temperature pollution sources,such as industrial emissions,coal furnaces,and automobile exhaust gases.However,filtration at pollution sources remains challenging because most existing air filters are not resistant to high temperature.Herein,heat-resistant polyimide(PI)nanofibrous air filters are fabricated via a simple and scalable solution blow-spinning method.These air filters show excellent thermal stability at high temperature up to 420℃.They exhibit a filtration efficiency as high as 99.73%at ambient temperature and over 97%at 300℃.In addition,a field test shows that the filters remove>97%of PM from the car exhaust fumes.Hence,the blow-spun PI nanofibrous membranes combined with the facile preparation strategy have great potential in high temperature air filtration fields and other similar applications such as water purification and protein separation.

Room-temperature production of silver-nanofiber film for large-area, transparent and flexible surface electromagnetic interference shielding

A kind of pollution known as electromagnetic interference(EMI),which results from ubiquitous usage of various electronic communication and military radar equipment,has been receiving increasing attention recently.However,large-area EMI shielding on transparent and/or curved surfaces,including building windows,curved glass wall,and special requirements spaces(SRSs),remains hard to achieve.In this paper,a silver nanofiber(AgNF)based flexible and transparent EMI shielding film was successfully assembled via a room-temperature roll-to-roll production method.For transparent application scenario,AgNF with 89%transmittance in visible range and 1μm thickness shows~20 dB shielding efficiency(EMI SE).On the other hand,total shielding(>50 dB)is obtained when the thickness of AgNF increases to 10μm,while its transmittance in visible range remains higher than 75%.Considering the facile and scale-free production technology,this material can be readily applied in large-scale,transparent,and/or SRSs EMI shielding.

An ultralight,flexible,and biocompatible all-fiber motion sensor for artificial intelligence wearable electronics

New-generation human body motion sensors for wearable electronics and intelligent medicine are required to comply with stringent requirements in terms of ultralight weight,flexibility,stability,biocompatibility,and extreme precision.However,conventional sensors are hard to fulfill all these criteria due to their rigid structure,high-density sensing materials used as the constituents,as well as hermetical and compact assembly strategy.Here,we report an ultralight sensing material based on radial anisotropic porous silver fiber(RAPSF),which has been manufactured by phase separation and temperature-controlled grain growth strategy on a modified blow-spinning system.The resistance of RAPSF could be dynamically adjusted depending on the deflected shape.Furthermore,an all-fiber motion sensor(AFMS)with an ultra-low density of 68.70 mg cm^(−3) and an overall weigh of 7.95 mg was fabricated via layer-by-layer assembly.The sensor exhibited outstanding flexibility,breathability,biocompatibility,and remarkable body motion recognition ability.Moreover,the AFMS was shown to have great potential as an artificial intelligence throat sensor for throat state identification at the accuracy above 85%,allowing one to spot the early onset of the viral throat illness.

A large-area AgNW-modified textile with high-performance electromagnetic interference shielding

Manufacturing a flexible,light,large-area,and high-efficiency electromagnetic shielding materials in a straightforward and cost-effective manner presently remains a significant challenge.In this work,we propose a conductive network design and verify its electromagnetic interference(EMI)shielding effectiveness(SE)by simulation.Using the structure and parameters obtained by simulation,we prepare a flexible EMI shielding material using silver nanowires(AgNWs)/polyvinyl butyral(PVB)ethanol solution and textile substructure via a facile immersing method.In the frequency range of 5-18 GHz,the AgNWs/PVB textile with 1.4 mm thickness achieves an EMI SE of 59 dB,which exceeds the requirements for commercial applications.Due to the low density of 56 mg/cm^(3),specific shielding effectiveness(SSE)of this material reaches 1053 dB m^(3)/g.It is found that the AgNWs/PVB textile is more resistant to washing with water and oxidation than AgNWs textile without a PVB protector.As a result,the conductivity of AgNWs/PVB textile exhibits no change after washing with water and varies slightly after being kept in hot air.We find that a signal monitor is unable to detect a signal emitted by a mobile phone from a jacket lined with AgNWs/PVB textile.AgNWs/PVB textile with these properties can be mass-produced as high-efficiency EMI shielding material for commercial applications.