PSS modified by 3-aminopropyltrimethoxysilane linking large-area GNPs/PSS to silicone rubber with stable interface combination for high sensitivity flexible resistive sensor

Abstract

Flexible resistive sensors based on crack structures have been widely studied in the field of electronic skin and health monitoring. However, it is still a challenge to develop resistive sensors with strong interface bonding forces due to the problem that the sensitive layer of traditional cracked sensors falls off easily. This paper reports a new type of graphene-based resistive sensor, which uses modified poly(sodium 4-phenylene sulfonate) and graphene nanosheets to prepare a highly conductive, fragile, film sensitive layer. Siloxane at the end of modified poly(sodium 4-phenylene sulfonate) is used to enhance the interface between the sensitive layer and the silicone rubber layer to prepare a flexible resistive sensor with a crack structure. The sensor has a high sensitivity (gauge factor up to 21980.28) and a high response speed (∼65 ms), with an effective working range of 0–4.7 % strain. The sensor has been successfully applied to human physiological signal detection. The neural network algorithm successfully predicted the corresponding blood pressure based on the pulse wave signal detected by the sensor. The average error of systolic blood pressure and diastolic blood pressure was 0.79 and 0.42 mmHg, and the error of ± 5 mmHg accounted for 91.2 % and 94.3 % of the total, respectively. The error value passed the Association for the Advancement of Medical Instrumentation standard, and reached the Class A standard of British Hypertension Society.