{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,11]],"date-time":"2026-04-11T18:33:16Z","timestamp":1775932396253,"version":"3.50.1"},"reference-count":37,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2022,1,9]],"date-time":"2022-01-09T00:00:00Z","timestamp":1641686400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100007297","name":"Office of Naval Research Global","doi-asserted-by":"publisher","award":["N62909-19-1-2119"],"award-info":[{"award-number":["N62909-19-1-2119"]}],"id":[{"id":"10.13039\/100007297","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>The electrical and electromechanical responses of ~200 \u00b5m thick extruded nanocomposite films comprising of 4 wt.% and 5 wt.% multiwall carbon nanotubes mixed with polypropylene are investigated under an alternating current (AC) and compared to their direct current (DC) response. The AC electrical response to frequency (f) and strain (piezoimpedance) is characterized using two configurations, namely one that promotes resistive dominance (resistive configuration) and the other that promotes the permittivity\/capacitive contribution (dielectric configuration). For the resistive configuration, the frequency response indicated a resistive\u2013capacitive (RC) behavior (negative phase angle, \u03b8), with a significant contribution of capacitance for frequencies of 104 Hz and above, depending on the nanotube content. The piezoimpedance characterization in the resistive configuration yielded an increasing impedance modulus (|Z|) and an increasing (negative) value of \u03b8 as the strain increased. The piezoimpedance sensitivity at f = 10 kHz was ~30% higher than the corresponding DC piezoresistive sensitivity, yielding a sensitivity factor of 9.9 for |Z| and a higher sensitivity factor (~12.7) for \u03b8. The dielectric configuration enhanced the permittivity contribution to impedance, but it was the least sensitive to strain.<\/jats:p>","DOI":"10.3390\/s22020484","type":"journal-article","created":{"date-parts":[[2022,1,9]],"date-time":"2022-01-09T23:08:26Z","timestamp":1641769706000},"page":"484","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["A Comparative Study of the Electrical and Electromechanical Responses of Carbon Nanotube\/Polypropylene Composites in Alternating and Direct Current"],"prefix":"10.3390","volume":"22","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-9225-0167","authenticated-orcid":false,"given":"Abraham","family":"Balam","sequence":"first","affiliation":[{"name":"Centro de Investigaci\u00f3n Cient\u00edfica de Yucat\u00e1n A.C., Unidad de Materiales, Calle 43 No. 130 x 32 y 34, Col. Chuburn\u00e1 de Hidalgo, M\u00e9rida 97205, Yucat\u00e1n, Mexico"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1539-0649","authenticated-orcid":false,"given":"Ra\u00fal","family":"Pech-Pist\u00e9","sequence":"additional","affiliation":[{"name":"Centro de Investigaci\u00f3n Cient\u00edfica de Yucat\u00e1n A.C., Unidad de Materiales, Calle 43 No. 130 x 32 y 34, Col. Chuburn\u00e1 de Hidalgo, M\u00e9rida 97205, Yucat\u00e1n, Mexico"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Zarel","family":"Valdez-Nava","sequence":"additional","affiliation":[{"name":"LAPLACE, Universit\u00e9 de Toulouse, CNRS, INPT, UPS, 31062 Toulouse CEDEX 9, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Fidel","family":"Gamboa","sequence":"additional","affiliation":[{"name":"Centro de Investigaci\u00f3n y de Estudios Avanzados, Unidad M\u00e9rida, Departamento de F\u00edsica Aplicada, Km. 6 Antigua Carretera a Progreso A.P. 73, Cordemex, M\u00e9rida 07360, Yucat\u00e1n, Mexico"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0956-5994","authenticated-orcid":false,"given":"Alejandro","family":"Castillo-Atoche","sequence":"additional","affiliation":[{"name":"Facultad de Ingenier\u00eda, Universidad Aut\u00f3noma de Yucat\u00e1n, Av. Industrias No Contaminantes por Perif\u00e9rico Norte A.P. 150, Cordemex, M\u00e9rida 97000, Yucat\u00e1n, Mexico"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0227-1758","authenticated-orcid":false,"given":"Francis","family":"Avil\u00e9s","sequence":"additional","affiliation":[{"name":"Centro de Investigaci\u00f3n Cient\u00edfica de Yucat\u00e1n A.C., Unidad de Materiales, Calle 43 No. 130 x 32 y 34, Col. Chuburn\u00e1 de Hidalgo, M\u00e9rida 97205, Yucat\u00e1n, Mexico"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2022,1,9]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1486","DOI":"10.1016\/j.compscitech.2008.06.018","article-title":"A review and analysis of electrical percolation in carbon nanotube polymer composites","volume":"69","author":"Bauhofer","year":"2009","journal-title":"Compos. Sci. Technol."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"461","DOI":"10.1016\/j.scriptamat.2007.05.035","article-title":"Electrical behavior of polypropylene\/multiwalled carbon nanotube nanocomposites with low percolation threshold","volume":"57","author":"Tjong","year":"2007","journal-title":"Scr. Mater."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1701159","DOI":"10.1002\/adem.201701159","article-title":"Piezoresistivity, Strain, and Damage Self-Sensing of Polymer Composites Filled with Carbon Nanostructures","volume":"20","year":"2018","journal-title":"Adv. Eng. Mater."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"112755","DOI":"10.1016\/j.sna.2021.112755","article-title":"Recent progress on fabrication of carbon nanotube-based flexible conductive networks for resistive-type strain sensors","volume":"327","author":"Yan","year":"2021","journal-title":"Sens. Actuators A Phys."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1227","DOI":"10.1016\/j.compscitech.2008.01.006","article-title":"Sensors and actuators based on carbon nanotubes and their composites: A review","volume":"68","author":"Li","year":"2008","journal-title":"Compos. Sci. Technol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"361","DOI":"10.1016\/j.snb.2007.03.018","article-title":"A highly selective chemical gas sensor based on functionalization of multi-walled carbon nanotubes with poly(ethylene glycol)","volume":"126","author":"Niu","year":"2007","journal-title":"Sens. Actuators B Chem."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"3022","DOI":"10.1016\/j.carbon.2006.05.014","article-title":"Processing-structure-multi-functional property relationship in carbon nanotube\/epoxy composites","volume":"44","author":"Thostenson","year":"2006","journal-title":"Carbon"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"108285","DOI":"10.1016\/j.compscitech.2020.108285","article-title":"An experimental study on the piezoresistive and mechanical behavior of carbon nanocomposites subject to high-rate elastic loading","volume":"198","author":"Hernandez","year":"2020","journal-title":"Compos. Sci. Technol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"15367","DOI":"10.1007\/s10853-020-05099-z","article-title":"A critical review of piezoresistivity and its application in electrical-resistance-based strain sensing","volume":"55","author":"Chung","year":"2020","journal-title":"J. Mater. Sci."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1020","DOI":"10.1016\/j.carbon.2020.11.070","article-title":"Boosting electrical and piezoresistive properties of polymer nanocomposites via hybrid carbon fillers: A review","volume":"173","author":"Ke","year":"2021","journal-title":"Carbon"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"7587","DOI":"10.1007\/s10853-013-7575-3","article-title":"Coupled electro-mechanical properties of multiwall carbon nanotube\/polypropylene composites for strain sensing applications","volume":"48","year":"2013","journal-title":"J. Mater. Sci."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"129","DOI":"10.1016\/j.compositesa.2013.01.004","article-title":"A comparison between strain sensing behaviors of carbon black\/polypropylene and carbon nanotubes\/polypropylene electrically conductive composites","volume":"48","author":"Zhao","year":"2013","journal-title":"Compos. Part A Appl. Sci. Manuf."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"14570","DOI":"10.1007\/s10853-021-06223-3","article-title":"Investigation of directional effects on the electrical conductivity and piezoresistivity of carbon nanotube\/polypropylene composites obtained by extrusion","volume":"56","author":"Balam","year":"2021","journal-title":"J. Mater. Sci."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"92","DOI":"10.1177\/1045389X14560367","article-title":"Influence of carbon nanotube on the piezoresistive behavior of multiwall carbon nanotube\/polymer composites","volume":"27","author":"Aviles","year":"2016","journal-title":"J. Intell. Mater. Syst. Struct."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"192","DOI":"10.1016\/j.compositesb.2016.09.061","article-title":"Piezoresistive properties of resin reinforced with carbon nanotubes for health-monitoring of aircraft primary structures","volume":"107","author":"Vertuccio","year":"2016","journal-title":"Compos. Part B Eng."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"221903","DOI":"10.1063\/1.4833756","article-title":"Ultrasensitive strain sensors of multiwalled carbon nanotube\/epoxy nanocomposite using dielectric loss tangent","volume":"103","author":"Alamusi","year":"2013","journal-title":"Appl. Phys. Lett."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"041118","DOI":"10.1063\/1.5089900","article-title":"Piezo-impedance response of carbon nanotube\/polydimethylsiloxane nanocomposites","volume":"7","author":"Jeon","year":"2019","journal-title":"APL Mater."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"61","DOI":"10.1016\/j.sna.2016.12.011","article-title":"Piezoresistive performance characterization of strain sensitive multi-walled carbon nanotube-epoxy nanocomposites","volume":"254","author":"Sanli","year":"2017","journal-title":"Sens. Actuators A Phys."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"18","DOI":"10.1016\/j.compscitech.2015.11.012","article-title":"Piezoresistive characterization of multi-walled carbon nanotube-epoxy based flexible strain sensitive films by impedance spectroscopy","volume":"122","author":"Sanli","year":"2016","journal-title":"Compos. Sci. Technol."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"337","DOI":"10.1002\/app.29685","article-title":"Piezoresistivity of silicone-rubber\/carbon black composites excited by Ac electrical field","volume":"113","author":"Wang","year":"2009","journal-title":"J. Appl. Polym. Sci."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"112332","DOI":"10.1016\/j.sna.2020.112332","article-title":"Impact of MWCNT concentration on the piezo-impedance response of porous MWCNT\/PDMS composites","volume":"315","author":"Lim","year":"2020","journal-title":"Sens. Actuators A Phys."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"42","DOI":"10.1016\/j.mechmat.2017.03.014","article-title":"Maxwell\u2013Wagner\u2013Sillars mechanism in the frequency dependence of electrical conductivity and dielectric permittivity of graphene-polymer nanocomposites","volume":"109","author":"Xia","year":"2017","journal-title":"Mech. Mater."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"747","DOI":"10.1177\/1045389X07079872","article-title":"Tailoring Piezoresistive Sensitivity of Multilayer Carbon Nanotube Composite Strain Sensors","volume":"19","author":"Loh","year":"2008","journal-title":"J. Intell. Mater. Syst. Struct."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"145","DOI":"10.1016\/j.compscitech.2017.11.008","article-title":"Interfacial polarization and dielectric properties of aligned carbon nanotubes\/polymer composites: The role of molecular polarity","volume":"154","author":"Sun","year":"2018","journal-title":"Compos. Sci. Technol."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1378","DOI":"10.1016\/j.carbon.2005.01.007","article-title":"Influence of dispersion states of carbon nanotubes on physical properties of epoxy nanocomposites","volume":"43","author":"Song","year":"2005","journal-title":"Carbon"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"413","DOI":"10.1016\/j.carbon.2018.08.070","article-title":"First report of capacitance-based self-sensing and in-plane electric permittivity of carbon fiber polymer-matrix composite","volume":"140","author":"Eddib","year":"2018","journal-title":"Carbon"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"447","DOI":"10.1016\/j.carbon.2019.01.062","article-title":"Capacitance-based self-sensing of flaws and stress in carbon-carbon composite, with reports of the electric permittivity, piezoelectricity and piezoresistivity","volume":"146","author":"Xi","year":"2019","journal-title":"Carbon"},{"key":"ref_28","unstructured":"(2014). Standard Test Method for Tensile Properties of Plastics. Standard No. ASTM D638."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"100161","DOI":"10.1016\/j.jcomc.2021.100161","article-title":"Electromechanical properties of carbon-nanostructured elastomeric composites measured by digital image correlation","volume":"5","year":"2021","journal-title":"Compos. Part C Open Access"},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Bird, J. (2017). Electrical and Electronic Principles and Technology, Routledge. [6th ed.].","DOI":"10.4324\/9781315561875"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"5023","DOI":"10.1016\/S0032-3861(03)00451-8","article-title":"Dielectric spectroscopy on melt processed polycarbonate\u2014Multiwalled carbon nanotube composites","volume":"44","author":"Dudkin","year":"2003","journal-title":"Polymer"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"639","DOI":"10.1007\/s42114-021-00287-0","article-title":"Enhanced dielectric properties of high glass transition temperature PDCPD\/CNT composites by frontal ring-opening metathesis polymerization","volume":"4","author":"Wang","year":"2021","journal-title":"Adv. Compos. Hybrid Mater."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"2027","DOI":"10.1023\/A:1004398514901","article-title":"Electric modulus and interfacial polarization in composite polymeric systems","volume":"33","author":"Tsangaris","year":"1998","journal-title":"J. Mater. Sci."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"2616","DOI":"10.1007\/s10853-015-9575-y","article-title":"Tailoring dielectric properties of polymer composites by controlling alignment of carbon nanotubes","volume":"51","author":"Liu","year":"2016","journal-title":"J. Mater. Sci."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"201402","DOI":"10.1103\/PhysRevB.64.201402","article-title":"Frequency-dependent electrical transport in carbon nanotubes","volume":"64","author":"Zhao","year":"2001","journal-title":"Phys. Rev. B"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"42","DOI":"10.1016\/j.compscitech.2013.02.004","article-title":"Estimation of contact resistance and its effect on electrical conductivity of CNT\/PEEK composites","volume":"79","author":"Mohiuddin","year":"2013","journal-title":"Compos. Sci. Technol."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"012024","DOI":"10.1088\/1757-899X\/77\/1\/012024","article-title":"Mechanical Pressure Induced Capacitance Changes of Polyisoprene\/Nanostructured Carbon Black Composite Samples","volume":"77","author":"Ozols","year":"2015","journal-title":"IOP Conf. Ser. Mater. Sci. Eng."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/2\/484\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,13]],"date-time":"2025-10-13T14:01:48Z","timestamp":1760364108000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/2\/484"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,1,9]]},"references-count":37,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2022,1]]}},"alternative-id":["s22020484"],"URL":"https:\/\/doi.org\/10.3390\/s22020484","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,1,9]]}}}