Effect of contact material and ambient humidity on the performance of MWCNT/PDMS multimodal deformation sensors

• Published in: Sensors and actuators. A. Physical. Vol. 283; pp. 1 - 8
• Main Authors: Leemets, Kaur, Mäeorg, Uno, Aabloo, Alvo, Tamm, Tarmo
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.11.2018; Elsevier BV
• Subjects: Construction materials; Contact angle; Contact material; Deformation; Deformation effects; Deformation sensor; Elastomers; Fillers; Humidity; Moisture; Multi wall carbon nanotubes; MWCNT; PDMS; Polydimethylsiloxane; Sensitivity; Sensors; Silicone resins; Skin; Wheatstone bridges; Deformation sensor; Contact material; MWCNT; Moisture; Humidity; PDMS
• ISSN: 0924-4247; 1873-3069
• DOI: 10.1016/j.sna.2018.09.042

[Display omitted] •Humidity effects the signal of resistive and capacitive PDMS/MWCNT deformation sensors.•The effect of humidity strongly depends on the contact materials used.•Carbon mesh contacts outperform copper in terms of both electrical and mechanical stability.•13-layer mechanical sensor distinguishing between elongation and bending simultaneously. The soft sensors and electronic skin concept often relies on composites based on an elastomer (like PDMS) with some conducting fillers (like carbon nanotubes). In this paper, the ambient moisture sensitivity of MWCNT/PDMS composite multimodal mechanical sensors is demonstrated and tested in both resistance and capacitance measurements. In addition to the sensitivity of the sensor material itself, the contact material used in the construction was found to play an important role. For our sensor design, the effects on the resistive part of the sensor are balanced out by using the Wheatstone bridge setup. While small, the effect of ambient humidity to the capacitive part of the sensor does indeed exist. For obtaining accurate deformation readings, the effect of humidity needs to be taken into account whenever dealing with PDMS based sensors.