A Simple and Efficient Strategy for Preparation of Flexible Strain Sensors Based on Marangoni Effect

Abstract

The Marangoni effect is a phenomenon of mass transfer between two fluids with different surface tensions, which has been used in many fields. In this paper, we prepared ultrathin conductive films with graphene (GN) and carbon nanotubes (CNTs) based on the Marangoni effect. The Marangoni self-assembled film exhibited excellent properties, showing a conductivity of 8.3 kΩ·sq−1, a transparency of 74% at 550 nm and a thickness of 28 nm when the mass ratio of CNTs and GN was 1:1. The conductive films were transferred to flexible substrates twice and fabricated face to face as strain sensors. The 3M4910-based strain sensors, which were prepared with a simple process and high material utilization rate, exhibited good sensitivity (GF = 5.7), a wide working range (193%) and satisfactory cyclic stability. The PDMS-based GN sensor showed high sensitivity (GF = 34), a wide working range (78%) and excellent stability (ε = 10%, > 8000 cycles). It has been proved that the sensors can be used to detect different joint movements of the human body and subtle movements, showing good application prospects in physiological signal detection.