Getting Under the Sensor's Skin: The Importance of Electrical Contact Characterization for Conductive Composite Elastomers
Abstract Conductive elastomer composites can be used as flexible, lightweight, and inexpensive sensors, but they require ohmic electrical contacts to ensure readout consistency, and such contacts can suffer from hysteresis, non‐ohmic behavior, and cyclic fatigue. This work investigates a common caus...
Saved in:
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Wiley-VCH
2025-04-01
|
| Series: | Advanced Electronic Materials |
| Subjects: | |
| Online Access: | https://doi.org/10.1002/aelm.202400848 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1849715351400480768 |
|---|---|
| author | Claire C. Onsager Lev Rovinsky Can C. Aygen Shira K. Cohen Noa Lachman Matthew A. Grayson |
| author_facet | Claire C. Onsager Lev Rovinsky Can C. Aygen Shira K. Cohen Noa Lachman Matthew A. Grayson |
| author_sort | Claire C. Onsager |
| collection | DOAJ |
| description | Abstract Conductive elastomer composites can be used as flexible, lightweight, and inexpensive sensors, but they require ohmic electrical contacts to ensure readout consistency, and such contacts can suffer from hysteresis, non‐ohmic behavior, and cyclic fatigue. This work investigates a common cause of non‐ohmic conduction in such composite contacts, namely the thin insulating layer native to the surface of most silicone rubber composites that have been infused with multi‐walled carbon nanotubes for piezoresistive sensing. Voltage sweep dc measurements of individual contacts on this surface layer behave as parallel head‐to‐tail diodes with asymmetric hysteresis. Frequency sweep ac measurements quantify the insulator thickness with a leaky capacitor model to be ∼1 µm, independent of nanotube concentration, much thicker than the apparent layer thickness as imaged with scanning electron microscopy. This analysis also confirms highly anisotropic bulk conduction, circa 100 times higher in‐plane than cross‐plane. To remove the surface layer, a simple surface abrasion is shown to achieve deep ohmic electrical contact to the elastomer bulk. A three‐terminal method for verifying ohmic contacts is demonstrated and works even when all contacts are non‐ohmic. This three‐terminal method be easily applied to other conductive polymers for contact quality‐testing. |
| format | Article |
| id | doaj-art-e072edc8a2eb4985a5cffe34284ea2ad |
| institution | DOAJ |
| issn | 2199-160X |
| language | English |
| publishDate | 2025-04-01 |
| publisher | Wiley-VCH |
| record_format | Article |
| series | Advanced Electronic Materials |
| spelling | doaj-art-e072edc8a2eb4985a5cffe34284ea2ad2025-08-20T03:13:26ZengWiley-VCHAdvanced Electronic Materials2199-160X2025-04-01115n/an/a10.1002/aelm.202400848Getting Under the Sensor's Skin: The Importance of Electrical Contact Characterization for Conductive Composite ElastomersClaire C. Onsager0Lev Rovinsky1Can C. Aygen2Shira K. Cohen3Noa Lachman4Matthew A. Grayson5Department of Electrical and Computer Engineering Northwestern University Evanston 60208 USADepartment of Materials Science and Engineering Faculty of Engineering Tel Aviv University P.O. Box 39040 Tel Aviv 6997801 IsraelDepartment of Electrical and Computer Engineering Northwestern University Evanston 60208 USADepartment of Materials Science and Engineering Faculty of Engineering Tel Aviv University P.O. Box 39040 Tel Aviv 6997801 IsraelDepartment of Materials Science and Engineering Faculty of Engineering Tel Aviv University P.O. Box 39040 Tel Aviv 6997801 IsraelDepartment of Electrical and Computer Engineering Northwestern University Evanston 60208 USAAbstract Conductive elastomer composites can be used as flexible, lightweight, and inexpensive sensors, but they require ohmic electrical contacts to ensure readout consistency, and such contacts can suffer from hysteresis, non‐ohmic behavior, and cyclic fatigue. This work investigates a common cause of non‐ohmic conduction in such composite contacts, namely the thin insulating layer native to the surface of most silicone rubber composites that have been infused with multi‐walled carbon nanotubes for piezoresistive sensing. Voltage sweep dc measurements of individual contacts on this surface layer behave as parallel head‐to‐tail diodes with asymmetric hysteresis. Frequency sweep ac measurements quantify the insulator thickness with a leaky capacitor model to be ∼1 µm, independent of nanotube concentration, much thicker than the apparent layer thickness as imaged with scanning electron microscopy. This analysis also confirms highly anisotropic bulk conduction, circa 100 times higher in‐plane than cross‐plane. To remove the surface layer, a simple surface abrasion is shown to achieve deep ohmic electrical contact to the elastomer bulk. A three‐terminal method for verifying ohmic contacts is demonstrated and works even when all contacts are non‐ohmic. This three‐terminal method be easily applied to other conductive polymers for contact quality‐testing.https://doi.org/10.1002/aelm.202400848carbon nanotubesconductive compositeselastomerselectrical measurementinsulating surface layerohmic contacts |
| spellingShingle | Claire C. Onsager Lev Rovinsky Can C. Aygen Shira K. Cohen Noa Lachman Matthew A. Grayson Getting Under the Sensor's Skin: The Importance of Electrical Contact Characterization for Conductive Composite Elastomers Advanced Electronic Materials carbon nanotubes conductive composites elastomers electrical measurement insulating surface layer ohmic contacts |
| title | Getting Under the Sensor's Skin: The Importance of Electrical Contact Characterization for Conductive Composite Elastomers |
| title_full | Getting Under the Sensor's Skin: The Importance of Electrical Contact Characterization for Conductive Composite Elastomers |
| title_fullStr | Getting Under the Sensor's Skin: The Importance of Electrical Contact Characterization for Conductive Composite Elastomers |
| title_full_unstemmed | Getting Under the Sensor's Skin: The Importance of Electrical Contact Characterization for Conductive Composite Elastomers |
| title_short | Getting Under the Sensor's Skin: The Importance of Electrical Contact Characterization for Conductive Composite Elastomers |
| title_sort | getting under the sensor s skin the importance of electrical contact characterization for conductive composite elastomers |
| topic | carbon nanotubes conductive composites elastomers electrical measurement insulating surface layer ohmic contacts |
| url | https://doi.org/10.1002/aelm.202400848 |
| work_keys_str_mv | AT claireconsager gettingunderthesensorsskintheimportanceofelectricalcontactcharacterizationforconductivecompositeelastomers AT levrovinsky gettingunderthesensorsskintheimportanceofelectricalcontactcharacterizationforconductivecompositeelastomers AT cancaygen gettingunderthesensorsskintheimportanceofelectricalcontactcharacterizationforconductivecompositeelastomers AT shirakcohen gettingunderthesensorsskintheimportanceofelectricalcontactcharacterizationforconductivecompositeelastomers AT noalachman gettingunderthesensorsskintheimportanceofelectricalcontactcharacterizationforconductivecompositeelastomers AT matthewagrayson gettingunderthesensorsskintheimportanceofelectricalcontactcharacterizationforconductivecompositeelastomers |