Conductive and Thermo-Responsive Composite Hydrogels with Poly(N-isopropylacrylamide) and Carbon Nanotubes Fabricated by Two-Step Photopolymerization
Biocompatible and conductive polymer hydrogels are the subject of intensive research in the bioengineering field because of their use in bioelectronic devices and for the fabrication of electro-responsive tissues and drug delivery systems. In this study, we report the synthesis of conductive composi...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2023-02-01
|
| Series: | Polymers |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2073-4360/15/4/1022 |
| _version_ | 1797618546605293568 |
|---|---|
| author | Gianluca Ciarleglio Elisa Toto Maria Gabriella Santonicola |
| author_facet | Gianluca Ciarleglio Elisa Toto Maria Gabriella Santonicola |
| author_sort | Gianluca Ciarleglio |
| collection | DOAJ |
| description | Biocompatible and conductive polymer hydrogels are the subject of intensive research in the bioengineering field because of their use in bioelectronic devices and for the fabrication of electro-responsive tissues and drug delivery systems. In this study, we report the synthesis of conductive composite hydrogels consisting of a poly(N-isopropylacrylamide) (PNIPAM) matrix embedding carboxyl-functionalized multi-walled carbon nanotubes (MWCNT-COOH) using a two-step photopolymerization method. Thermo-responsive hydrogels with controlled hydrophilicity and conductivity were prepared by varying the carbon nanotube concentration in the range 0.5–3 wt%. The thermal response of the PNIPAM-based composite hydrogels was measured by differential scanning calorimetry with both ultrapure water and PBS solution as swelling liquid. Results show that the endothermic peak associated with the temperature-induced volume phase transition (VPT) shifts to higher temperatures upon increasing the concentration of the nanotubes, indicating that more energy is required to dissociate the hydrogen bonds of the polymer/filler network. In PBS solution, the swelling ratios and the VPT temperatures of the composite hydrogels are reduced because of salt-induced screening of the oppositely charged polymer/filler assembly, and the electrical resistivity decreases by a factor of 10 with respect to the water-swollen hydrogels. |
| first_indexed | 2024-03-11T08:14:16Z |
| format | Article |
| id | doaj.art-ddba4682b5f04f099a62f53345b07432 |
| institution | Directory Open Access Journal |
| issn | 2073-4360 |
| language | English |
| last_indexed | 2024-03-11T08:14:16Z |
| publishDate | 2023-02-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Polymers |
| spelling | doaj.art-ddba4682b5f04f099a62f53345b074322023-11-16T22:53:05ZengMDPI AGPolymers2073-43602023-02-01154102210.3390/polym15041022Conductive and Thermo-Responsive Composite Hydrogels with Poly(N-isopropylacrylamide) and Carbon Nanotubes Fabricated by Two-Step PhotopolymerizationGianluca Ciarleglio0Elisa Toto1Maria Gabriella Santonicola2Department of Chemical Engineering Materials Environment, Sapienza University of Rome, Via del Castro Laurenziano 7, 00161 Rome, ItalyDepartment of Chemical Engineering Materials Environment, Sapienza University of Rome, Via del Castro Laurenziano 7, 00161 Rome, ItalyDepartment of Chemical Engineering Materials Environment, Sapienza University of Rome, Via del Castro Laurenziano 7, 00161 Rome, ItalyBiocompatible and conductive polymer hydrogels are the subject of intensive research in the bioengineering field because of their use in bioelectronic devices and for the fabrication of electro-responsive tissues and drug delivery systems. In this study, we report the synthesis of conductive composite hydrogels consisting of a poly(N-isopropylacrylamide) (PNIPAM) matrix embedding carboxyl-functionalized multi-walled carbon nanotubes (MWCNT-COOH) using a two-step photopolymerization method. Thermo-responsive hydrogels with controlled hydrophilicity and conductivity were prepared by varying the carbon nanotube concentration in the range 0.5–3 wt%. The thermal response of the PNIPAM-based composite hydrogels was measured by differential scanning calorimetry with both ultrapure water and PBS solution as swelling liquid. Results show that the endothermic peak associated with the temperature-induced volume phase transition (VPT) shifts to higher temperatures upon increasing the concentration of the nanotubes, indicating that more energy is required to dissociate the hydrogen bonds of the polymer/filler network. In PBS solution, the swelling ratios and the VPT temperatures of the composite hydrogels are reduced because of salt-induced screening of the oppositely charged polymer/filler assembly, and the electrical resistivity decreases by a factor of 10 with respect to the water-swollen hydrogels.https://www.mdpi.com/2073-4360/15/4/1022poly(N-isopropylacrylamide)hydrogelscarbon nanotubesphotopolymerizationcalorimetry |
| spellingShingle | Gianluca Ciarleglio Elisa Toto Maria Gabriella Santonicola Conductive and Thermo-Responsive Composite Hydrogels with Poly(N-isopropylacrylamide) and Carbon Nanotubes Fabricated by Two-Step Photopolymerization Polymers poly(N-isopropylacrylamide) hydrogels carbon nanotubes photopolymerization calorimetry |
| title | Conductive and Thermo-Responsive Composite Hydrogels with Poly(N-isopropylacrylamide) and Carbon Nanotubes Fabricated by Two-Step Photopolymerization |
| title_full | Conductive and Thermo-Responsive Composite Hydrogels with Poly(N-isopropylacrylamide) and Carbon Nanotubes Fabricated by Two-Step Photopolymerization |
| title_fullStr | Conductive and Thermo-Responsive Composite Hydrogels with Poly(N-isopropylacrylamide) and Carbon Nanotubes Fabricated by Two-Step Photopolymerization |
| title_full_unstemmed | Conductive and Thermo-Responsive Composite Hydrogels with Poly(N-isopropylacrylamide) and Carbon Nanotubes Fabricated by Two-Step Photopolymerization |
| title_short | Conductive and Thermo-Responsive Composite Hydrogels with Poly(N-isopropylacrylamide) and Carbon Nanotubes Fabricated by Two-Step Photopolymerization |
| title_sort | conductive and thermo responsive composite hydrogels with poly n isopropylacrylamide and carbon nanotubes fabricated by two step photopolymerization |
| topic | poly(N-isopropylacrylamide) hydrogels carbon nanotubes photopolymerization calorimetry |
| url | https://www.mdpi.com/2073-4360/15/4/1022 |
| work_keys_str_mv | AT gianlucaciarleglio conductiveandthermoresponsivecompositehydrogelswithpolynisopropylacrylamideandcarbonnanotubesfabricatedbytwostepphotopolymerization AT elisatoto conductiveandthermoresponsivecompositehydrogelswithpolynisopropylacrylamideandcarbonnanotubesfabricatedbytwostepphotopolymerization AT mariagabriellasantonicola conductiveandthermoresponsivecompositehydrogelswithpolynisopropylacrylamideandcarbonnanotubesfabricatedbytwostepphotopolymerization |