Preparation and properties of a novel sandwich structure polydimethylsiloxane/polyvinylidene fluoride-Ag nanowires/polydimethylsiloxane flexible strain sensor

In order to improve the performance of the flexible strain sensor, the polyvinylidene fluoride (PVDF) electrospinning film was prepared by electrospinning, and the self-made Ag nanowires (AgNWs) were suction filtered on the surface of the PVDF electrospinning film as a conductive layer. A multi-layer sandwich polydimethylsiloxane (PDMS)/PVDF-AgNWs/PDMS flexible strain sensor with different content of AgNWs in a series of conductive layers was prepared by using PDMS to cure the conductive layer on both sides. The performance of the PDMS/PVDF-AgNWs/PDMS sensor was characterized and analyzed. The results show that the introduction of the electrospun membrane significantly improves the performance of the PDMS/PVDF-AgNWs/PDMS flexible strain sensor, reduces the hysteresis, increases the sensitivity and repeatability and greatly improves the service life of the PDMS/PVDF-AgNWs/PDMS sensor. When the content of AgNWs in the conductive layer is 0.030 g, and the strain reaches 10%, the guage factor which can directly reflect the sensitivity of the flexible strain sensor can reach 143.85. After 30 days of repeatable test on the self-made sensor, the initial resistance value of the PDMS/PVDF-AgNWs/PDMS flexible strain sensor is only increased by about 2 Ω compared with the initial test under the condition of setting the displacement of 5 mm and stretching 20 times per day. The resistance value of PDMS/PVDF-AgNWs/PDMS​​​​​​​ flexible strain sensor compared with the maximum displacement value is negligible.