Feb 11, 2010
Nanoweb upgrades sensor
Electrospun nanofibrous membranes typically have fibre diameters in the range 100–500 nm, but properties such as surface area and porosity become more significant when the fibre diameter falls below 20 nm. The major challenge for developers is to come up with robust methods for manufacturing extremely small nanofibres in large quantities and with a uniform size.
Researchers in China and the US have taken a step in this direction by fabricating electrospun polymeric membranes that contain nanowebs. As shown in the figure, the average diameter of the polyacrylic acid (PAA) nanowebs is less than 20 nm, which is about one order of magnitude less than conventional electrospun fibres. The group has successfully prepared various nanowebs based on different polymer systems and has grasped the rules that regulate the pore size of the structure.
Their remarkable specific surface area and high porosity make electrospun nanowebs highly attractive candidates for use in a range of devices including ultrasensitive sensors.
The team has fabricated a novel humidity sensor by using an electrospinning technique to deposit a network of PAA nanowebs on a quartz crystal microbalance (QCM). The highly sensitive coating produced a response that increased by more than two orders of magnitude as relative humidity (RH) increased from 6 to 95% at room temperature.
In addition, nanowebs have the potential to be used as ultra-fine filters to intercept viruses and bacteria, such as H1N1 virus, SARS virus, E. coli, etc.
Full details can be found in the journal Nanotechnology.
About the author
Bin Ding is a professor at Donghua University, China. His primary research interests include fabrication of nanostructured materials, gas sensors, biosensors, catalysts and filters. Prof. Jianyong Yu is vice-president of Donghua University. Xianfeng Wang is a PhD candidate at the Modern Textile Institute, Donghua University. Moran Wang is a professor at Los Alamos National Laboratory, US. Prof. Fukui Pan is dean of the College of Textiles and Fashion, Qingdao University, China.