Activation Free SAM-Assisted Silver Electroless Metallization of Textile for Strain Sensor Application

Wednesday, October 14, 2015: 18:10
106-C (Phoenix Convention Center)
A. Molazemhosseini, E. Cattarinuzzi, D. Gastaldi, P. Vena (Politecnico di Milano), and L. Magagnin (Politecnico di Milano)
Flexible, stretchable and wearable electronic devices are becoming more
demanding due to their facile interaction with human body. These devices can be
easily mount on clothing or directly attached onto skin. Among wearable
electronic devices, highly stretchable and sensitive strain sensors have drawn lots
of attention for monitoring human body motions. There are number of
requirements for a high performance strain sensor including high sensitivity (i.e.,
gauge factor (GF)), high stretchability, fast response, high stability and low
fabrication cost. Personal health monitoring, sport performance monitoring and
human motion capturing for entertainment systems are the most popular
applications for a high performance strain senor.
In this paper, we present a cost effective simple strain sensor fabricated through
silver electroless metallization of commercial polyester fabric. To avoid using
SnCl2 or PdCl2 activation solutions, a silica-like layer was formed on polyester
fabric using an acetone based aminopropyltrimethoxysilane (APTMS) solution
followed by UV irradiation. Once the anchoring sites for later silanization were
developed, a toluene based solution of (3-Mercaptopropyl)trimethoxysilane
(MPTMS) were used to activate the polyester fabric. Silver electroless
metallization was carried out on activated polyester using silver nitrate salt and
glucose as reducing agent. Scanning electron microscopy (SEM) and X-ray
diffraction spectroscopy (XRD) were used to characterize the Ag-coated polyester.
A thin silver coating (<1 μm) with uniform morphology and high purity was
deposited on polyester. The conductive fabric was cut into strips of 5mm
thickness for stretch-conductivity measurements. A micro-tensile machine with
an in-situ confocal microscope was coupled with a digital multimeter (2-point
probing) to investigate strain dependence electrical resistivity. In-situ confocal
imaging was used to investigate the micromechanical mechanisms responsible for
changes in resistivity during stretching. A linear decrease in electrical resistance
was detected by stetching untill it reaches to a platu. The results of stretch–conductivity
measurements suggest the potential application of Ag/Polyester for
strain sensors.