{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T01:19:55Z","timestamp":1760059195611,"version":"build-2065373602"},"reference-count":13,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2025,5,28]],"date-time":"2025-05-28T00:00:00Z","timestamp":1748390400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"PRR and NextGenerationEU","award":["C644914747-00000023","UID 00481"],"award-info":[{"award-number":["C644914747-00000023","UID 00481"]}]},{"name":"Mechanical Technology and Automation (TEMA)","award":["C644914747-00000023","UID 00481"],"award-info":[{"award-number":["C644914747-00000023","UID 00481"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Polymers"],"abstract":"<jats:p>This study explores the vibrational behavior of Thermoformed Magneto-Piezoelectrets (TMPs), multifunctional materials consisting of thermoformed piezoelectrets with open tubular channels integrated with an additional magnetic layer. The inverse piezoelectric effect was characterized using laser vibrometry analysis, measuring the mechanical response of TMPs subjected to electrical excitation over a frequency range of 0\u201320 kHz. Vibrational analysis was conducted at 144 spatial points, enabling the construction of detailed three-dimensional (3D) maps of the vibration operational modes and the spatial distribution of the piezoelectric coefficient (d33). The results demonstrated significant frequency-dependent behavior, with open channels exhibiting pronounced resonance peaks, whereas valleys displayed smoother and more uniform responses due to enhanced damping effects. The observed heterogeneity in vibrational behavior is attributed to structural variations, material composition, and anisotropic coupling between the piezoelectric and magnetic properties. The findings presented in this research provide a comprehensive understanding of the development and utilization of TMPs, offering parameters for enhancing their application and supporting new discoveries in studies related to the fabrication of novel thermoformed piezoelectric sensors.<\/jats:p>","DOI":"10.3390\/polym17111506","type":"journal-article","created":{"date-parts":[[2025,5,28]],"date-time":"2025-05-28T10:21:13Z","timestamp":1748427673000},"page":"1506","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Investigation of the Vibrational Behavior of Thermoformed Magnetic Piezoelectrets"],"prefix":"10.3390","volume":"17","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-5758-5578","authenticated-orcid":false,"given":"Am\u00e9lia M.","family":"Santos","sequence":"first","affiliation":[{"name":"TEMA\u2014Centre for Mechanical Technology and Automation, Department of Mechanical Engineering, University of Aveiro, 3810-193 Aveiro, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5328-1705","authenticated-orcid":false,"given":"Rui A. S.","family":"Moreira","sequence":"additional","affiliation":[{"name":"TEMA\u2014Centre for Mechanical Technology and Automation, Department of Mechanical Engineering, University of Aveiro, 3810-193 Aveiro, Portugal"},{"name":"LASI\u2014Intelligent Systems Associate Laboratory, 4800-058 Guimar\u00e3es, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0009-0009-0004-1332","authenticated-orcid":false,"given":"Leonardo S.","family":"Caires","sequence":"additional","affiliation":[{"name":"TEMA\u2014Centre for Mechanical Technology and Automation, Department of Mechanical Engineering, University of Aveiro, 3810-193 Aveiro, Portugal"},{"name":"Department of Electrical Engineering, Federal Institute of Bahia, Vitoria da Conquista 45029-000, BA, Brazil"}]},{"ORCID":"https:\/\/orcid.org\/0009-0006-5830-1537","authenticated-orcid":false,"given":"Ronaldo M.","family":"Lima","sequence":"additional","affiliation":[{"name":"TEMA\u2014Centre for Mechanical Technology and Automation, Department of Mechanical Engineering, University of Aveiro, 3810-193 Aveiro, Portugal"},{"name":"Department of Physics, Federal Institute of Sergipe, Lagarto 49400-000, SE, Brazil"}]},{"ORCID":"https:\/\/orcid.org\/0009-0002-8695-1079","authenticated-orcid":false,"given":"Elvio P.","family":"Silva","sequence":"additional","affiliation":[{"name":"TEMA\u2014Centre for Mechanical Technology and Automation, Department of Mechanical Engineering, University of Aveiro, 3810-193 Aveiro, Portugal"},{"name":"Department of Electrical Engineering, Federal Institute of Bahia, Vitoria da Conquista 45029-000, BA, Brazil"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4724-9252","authenticated-orcid":false,"given":"Polyane A.","family":"Santos","sequence":"additional","affiliation":[{"name":"TEMA\u2014Centre for Mechanical Technology and Automation, Department of Mechanical Engineering, University of Aveiro, 3810-193 Aveiro, Portugal"},{"name":"Department of Electrical Engineering, Federal Institute of Bahia, Vitoria da Conquista 45029-000, BA, Brazil"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8819-8792","authenticated-orcid":false,"given":"J\u00e9ssica F.","family":"Alves","sequence":"additional","affiliation":[{"name":"Department of Electrical and Computer Engineering, University of S\u00e3o Paulo, S\u00e3o Carlos 13566-590, SP, Brazil"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0054-0771","authenticated-orcid":false,"given":"Sergio M. O.","family":"Tavares","sequence":"additional","affiliation":[{"name":"TEMA\u2014Centre for Mechanical Technology and Automation, Department of Mechanical Engineering, University of Aveiro, 3810-193 Aveiro, Portugal"},{"name":"LASI\u2014Intelligent Systems Associate Laboratory, 4800-058 Guimar\u00e3es, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4980-7011","authenticated-orcid":false,"given":"Kenedy Marconi G.","family":"Santos","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, Federal Institute of Bahia, Vitoria da Conquista 45029-000, BA, Brazil"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6776-9824","authenticated-orcid":false,"given":"Ruy A. P.","family":"Altafim","sequence":"additional","affiliation":[{"name":"Computer System Department, Informatic Center, Federal University of Paraiba, Jo\u00e3o Pessoa 58055-000, PB, Brazil"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2248-9305","authenticated-orcid":false,"given":"Ruy A. C.","family":"Altafim","sequence":"additional","affiliation":[{"name":"Department of Electrical and Computer Engineering, University of S\u00e3o Paulo, S\u00e3o Carlos 13566-590, SP, Brazil"}]}],"member":"1968","published-online":{"date-parts":[[2025,5,28]]},"reference":[{"key":"ref_1","unstructured":"Altafim, R.A., Basso, H.C., Neto, L.G., Lima, L., Altafim, R.A., and De Aquino, C.V. (2005, January 16\u201319). Piezoelectricity in multi-air voids electrets. Proceedings of the Annual Report\u2014Conference on Electrical Insulation and Dielectric Phenomena, CEIDP, Nashville, TN, USA."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"De Carvalho, F.J., Altafim, R.A.C., Assagra, Y.A.O., Borges, B.H.V., and Altafim, R.A.P. (2016, January 16\u201319). Electric circuit model for simulating ferroelectrets with open-tubular channels. Proceedings of the 2016 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP), Toronto, ON, Canada.","DOI":"10.1109\/CEIDP.2016.7785625"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"48884","DOI":"10.1002\/app.48884","article-title":"Piezoelectric polymer microfiber-based composite for the flexible ultra-sensitive pressure sensor","volume":"137","author":"Nguyen","year":"2019","journal-title":"J. Appl. Polym. Sci."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Tich\u00fd, J., Erhart, J., Kittinger, E., and P\u0159\u00edvratsk\u00e1, J. (2010). Fundamentals of Piezoelectric Sensorics: Mechanical, Dielectric, and Thermodynamical Properties of Piezoelectric Materials, Springer.","DOI":"10.1007\/978-3-540-68427-5"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"174105","DOI":"10.1063\/1.5041374","article-title":"Template-based fluoroethylenepropylene ferroelectrets with enhanced thermal stability of piezoelectricity","volume":"124","author":"Rychkov","year":"2018","journal-title":"J. Appl. Phys."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Sun, Z., Zhang, X., Xia, Z., Qiu, X., Wirges, W., Gerhard, R., Zeng, C., Zhang, C., and Wang, B. (2011, January 28\u201331). Investigation into polarization and piezoelectricity in polymer films with artificial void structure. Proceedings of the 2011\u201414th International Symposium on Electrets, Montpellier, France.","DOI":"10.1109\/ISE.2011.6084963"},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Fang, P., Wirges, W., Gerhard, R., and Zirkel, L. (2008, January 15\u201317). Charging conditions for cellular-polymer ferroelectrets with enhanced thermal stability. Proceedings of the 2008 13th International Symposium on Electrets, Tokyo, Japan.","DOI":"10.1109\/ISE.2008.4814079"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"014106","DOI":"10.1063\/1.3159039","article-title":"Template-based fluoroethylenepropylene piezoelectrets with tubular channels for transducer applications","volume":"106","author":"Altafim","year":"2009","journal-title":"J. Appl. Phys."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"979","DOI":"10.1109\/TDEI.2006.247822","article-title":"Piezoelectrets from thermo-formed bubble structures of fluoropolymer-electret films","volume":"13","author":"Altafim","year":"2006","journal-title":"IEEE Trans. Dielectr. Electr. Insul."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"965","DOI":"10.1007\/s00339-012-6848-z","article-title":"Fluoropolymer piezoelectrets with tubular channels: Resonance behavior controlled by channel geometry","volume":"107","author":"Altafim","year":"2012","journal-title":"Appl. Phys. A Mater. Sci. Process."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Altafim, R.A., Altafim, R.A., Basso, H.C., Qiu, X., Wirges, W., and Gerhard, R. (2011, January 16\u201319). Fluoroethylenepropylene ferroelectrets with superimposed multi-layer tubular void channels. Proceedings of the Annual Report\u2014Conference on Electrical Insulation and Dielectric Phenomena, CEIDP, Cancun, Mexico.","DOI":"10.1109\/CEIDP.2011.6232614"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"241901","DOI":"10.1063\/5.0071231","article-title":"Piezoelectric-magnetic behavior of ferroelectrets coated with magnetic layer","volume":"119","author":"Altafim","year":"2021","journal-title":"Appl. Phys. Lett."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"29149","DOI":"10.1109\/JSEN.2024.3431990","article-title":"Current Transducer Based on Thermoformed Piezo-Magnetic-Electrets","volume":"24","author":"Santos","year":"2024","journal-title":"IEEE Sens. J."}],"container-title":["Polymers"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2073-4360\/17\/11\/1506\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T17:42:30Z","timestamp":1760031750000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2073-4360\/17\/11\/1506"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,5,28]]},"references-count":13,"journal-issue":{"issue":"11","published-online":{"date-parts":[[2025,6]]}},"alternative-id":["polym17111506"],"URL":"https:\/\/doi.org\/10.3390\/polym17111506","relation":{},"ISSN":["2073-4360"],"issn-type":[{"type":"electronic","value":"2073-4360"}],"subject":[],"published":{"date-parts":[[2025,5,28]]}}}