Highly sensitive, flexible and biocompatible temperature sensor utilizing ultra-long Au@AgNW-based polymeric nanocomposites. Issue 5 (11th January 2022)

• Record Type: Journal Article
• Authors: Kumar, Amit; Shaikh, Muhammad Omar; Kumar, R. K. Rakesh; Dutt, Karishma; Pan, Cheng-Tang; Chuang, Cheng-Hsin
• Is Part Of: Nanoscale. Volume 14:Issue 5(2022)
• Page Start: 1742
• Page End: 1754
• Publication Date: 2022-01-11
• Subjects: Nanoscience -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/d1nr05068k
• Languages: English
• ISSNs: 2040-3364

Abstract

Abstract : Ultralong and biocompatible Au@AgNWs were synthesized and implemented as conductive filler to prepare a flexible and conductive polymeric nanocomposite. A novel temperature sensing mechanism based on the thermosensitive PEG-coated Au@AgNWs has been successfully demonstrated. Abstract : Owing to their excellent sensitivity, stretchability, flexibility and conductivity, polymeric nanocomposites with conductive fillers have shown promise for a wide range of applications in bioelectronics and wearable devices. Herein, we report on the development of a flexible and biocompatible polymeric nanocomposite comprising ultra-long Ag–Au core–sheath nanowires (Au@AgNWs) dispersed in elastomeric media to fabricate a high-resolution wearable temperature sensor. Ultra-long AgNWs with an aspect ratio of about 1500 were synthesized using a Ca 2+ ion-mediated facile one-pot polyol process. To enhance the biocompatibility and anti-oxidative property of the AgNWs, a 10–20 nm gold (Au) layer was conformably deposited without affecting the original nanowire morphology. The core–sheath structure of Au@AgNWs was characterized using HRTEM and EDS elemental mapping while the biocompatibility and anti-oxidative properties were tested using hydrogen peroxide (H2 O2 ) etching in solution phase. Finally, the fabricated nanowires were used to prepare the Au@AgNW–poly-ethylene glycol (PEG)–polyurethane (PU)-based nanocomposite ink which can be printed on interdigitated electrodes to fabricate a thermoresistive temperature sensor with negative temperature coefficient (NTC) of resistance and quick response time (<100 s). The Au@AgNW–PEG–PU nanocomposite was characterized in detail and a novel temperature sensing mechanism based on controlling the internanowire distance of the PEG coated Au@AgNWs percolation by means of capillarity force among the nanowires as a result of the glass transition temperature of thermosensitive PEG was demonstrated. The proposed printable temperature sensor is flexible and biocompatible and shows promise for a range of wearable applications.