Electrospun PCL Filtration Membranes Enhanced with an Electrosprayed Lignin Coating to Control Wettability and Anti-Bacterial Properties
This study reports on the two-step manufacturing process of a filtration media obtained by first electrospinning a layer of polycaprolactone (PCL) non-woven fibers onto a paper filter backing and subsequently coating it by electrospraying with a second layer made of pure acidolysis lignin. The manuf...
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| Format: | Article |
| Language: | English |
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MDPI AG
2024-03-01
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| Series: | Polymers |
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| Online Access: | https://www.mdpi.com/2073-4360/16/5/674 |
| _version_ | 1797263979553226752 |
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| author | Sara Bergamasco Noemi Fiaschini Luis Alexander Hein Marco Brecciaroli Roberta Vitali Manuela Romagnoli Antonio Rinaldi |
| author_facet | Sara Bergamasco Noemi Fiaschini Luis Alexander Hein Marco Brecciaroli Roberta Vitali Manuela Romagnoli Antonio Rinaldi |
| author_sort | Sara Bergamasco |
| collection | DOAJ |
| description | This study reports on the two-step manufacturing process of a filtration media obtained by first electrospinning a layer of polycaprolactone (PCL) non-woven fibers onto a paper filter backing and subsequently coating it by electrospraying with a second layer made of pure acidolysis lignin. The manufacturing of pure lignin coatings by solution electrospraying represents a novel development that requires fine control of the underlying electrodynamic processing. The effect of increasing deposition time on the lignin coating was investigated for electrospray time from 2.5 min to 120 min. Microstructural and physical characterization included SEM, surface roughness analysis, porosity tests, permeability tests by a Gurley densometer, ATR-FTIR analysis, and contact angle measurements vs. both water and oil. The results indicate that, from a functional viewpoint, such a natural coating endowed the membrane with an amphiphilic behavior that enabled modulating the nature of the bare PCL non-woven substrate. Accordingly, the intrinsic hydrophobic behavior of bare PCL electrospun fibers could be reduced, with a marked decrease already for a thin coating of less than 50 nm. Instead, the wettability of PCL vs. apolar liquids was altered in a less predictable manner, i.e., producing an initial increase of the oil contact angles (OCA) for thin lignin coating, followed by a steady decrease in OCA for higher densities of deposited lignin. To highlight the effect of the lignin type on the results, two grades of oak (AL-OA) of the <i>Quercus cerris</i> L. species and eucalyptus (AL-EU) of the <i>Eucalyptus camaldulensis</i> Dehnh species were compared throughout the investigation. All grades of lignin yielded coatings with measurable antibacterial properties, which were investigated against <i>Staphylococcus aureus</i> and <i>Escherichia coli</i>, yielding superior results for AL-EU. Remarkably, the lignin coatings did not change overall porosity but smoothed the surface roughness and allowed modulating air permeability, which is relevant for filtration applications. The findings are relevant for applications of this abundant biopolymer not only for filtration but also in biotechnology, health, packaging, and circular economy applications in general, where the reuse of such natural byproducts also brings a fundamental demanufacturing advantage. |
| first_indexed | 2024-04-25T00:21:37Z |
| format | Article |
| id | doaj.art-e356a6079dc449d5ac48fe19de91748e |
| institution | Directory Open Access Journal |
| issn | 2073-4360 |
| language | English |
| last_indexed | 2024-04-25T00:21:37Z |
| publishDate | 2024-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Polymers |
| spelling | doaj.art-e356a6079dc449d5ac48fe19de91748e2024-03-12T16:53:39ZengMDPI AGPolymers2073-43602024-03-0116567410.3390/polym16050674Electrospun PCL Filtration Membranes Enhanced with an Electrosprayed Lignin Coating to Control Wettability and Anti-Bacterial PropertiesSara Bergamasco0Noemi Fiaschini1Luis Alexander Hein2Marco Brecciaroli3Roberta Vitali4Manuela Romagnoli5Antonio Rinaldi6Department for Innovation in Biological, Agro-Food and Forest Systems (DIBAF), University of Tuscia, Via San Camillo de Lellis snc, 01100 Viterbo, ItalyNANOFABER S.r.l., Via Anguillarese 301, 00123 Rome, ItalyNANOFABER S.r.l., Via Anguillarese 301, 00123 Rome, ItalySimitecno srl, 00173 Rome, ItalySSPT-TECS-TEB Laboratory, ENEA—Italian National Agency for New Technologies, Energy and Sustainable Economic Development, Via Anguillarese 301, 00123 Rome, ItalyDepartment for Innovation in Biological, Agro-Food and Forest Systems (DIBAF), University of Tuscia, Via San Camillo de Lellis snc, 01100 Viterbo, ItalySSPT-PROMAS-MATPRO Laboratory, ENEA—Italian National Agency for New Technologies, Energy and Sustainable Economic Development, Via Anguillarese 301, 00123 Rome, ItalyThis study reports on the two-step manufacturing process of a filtration media obtained by first electrospinning a layer of polycaprolactone (PCL) non-woven fibers onto a paper filter backing and subsequently coating it by electrospraying with a second layer made of pure acidolysis lignin. The manufacturing of pure lignin coatings by solution electrospraying represents a novel development that requires fine control of the underlying electrodynamic processing. The effect of increasing deposition time on the lignin coating was investigated for electrospray time from 2.5 min to 120 min. Microstructural and physical characterization included SEM, surface roughness analysis, porosity tests, permeability tests by a Gurley densometer, ATR-FTIR analysis, and contact angle measurements vs. both water and oil. The results indicate that, from a functional viewpoint, such a natural coating endowed the membrane with an amphiphilic behavior that enabled modulating the nature of the bare PCL non-woven substrate. Accordingly, the intrinsic hydrophobic behavior of bare PCL electrospun fibers could be reduced, with a marked decrease already for a thin coating of less than 50 nm. Instead, the wettability of PCL vs. apolar liquids was altered in a less predictable manner, i.e., producing an initial increase of the oil contact angles (OCA) for thin lignin coating, followed by a steady decrease in OCA for higher densities of deposited lignin. To highlight the effect of the lignin type on the results, two grades of oak (AL-OA) of the <i>Quercus cerris</i> L. species and eucalyptus (AL-EU) of the <i>Eucalyptus camaldulensis</i> Dehnh species were compared throughout the investigation. All grades of lignin yielded coatings with measurable antibacterial properties, which were investigated against <i>Staphylococcus aureus</i> and <i>Escherichia coli</i>, yielding superior results for AL-EU. Remarkably, the lignin coatings did not change overall porosity but smoothed the surface roughness and allowed modulating air permeability, which is relevant for filtration applications. The findings are relevant for applications of this abundant biopolymer not only for filtration but also in biotechnology, health, packaging, and circular economy applications in general, where the reuse of such natural byproducts also brings a fundamental demanufacturing advantage.https://www.mdpi.com/2073-4360/16/5/674electrospinningelectrosprayingligninoakeucalyptusPCL |
| spellingShingle | Sara Bergamasco Noemi Fiaschini Luis Alexander Hein Marco Brecciaroli Roberta Vitali Manuela Romagnoli Antonio Rinaldi Electrospun PCL Filtration Membranes Enhanced with an Electrosprayed Lignin Coating to Control Wettability and Anti-Bacterial Properties Polymers electrospinning electrospraying lignin oak eucalyptus PCL |
| title | Electrospun PCL Filtration Membranes Enhanced with an Electrosprayed Lignin Coating to Control Wettability and Anti-Bacterial Properties |
| title_full | Electrospun PCL Filtration Membranes Enhanced with an Electrosprayed Lignin Coating to Control Wettability and Anti-Bacterial Properties |
| title_fullStr | Electrospun PCL Filtration Membranes Enhanced with an Electrosprayed Lignin Coating to Control Wettability and Anti-Bacterial Properties |
| title_full_unstemmed | Electrospun PCL Filtration Membranes Enhanced with an Electrosprayed Lignin Coating to Control Wettability and Anti-Bacterial Properties |
| title_short | Electrospun PCL Filtration Membranes Enhanced with an Electrosprayed Lignin Coating to Control Wettability and Anti-Bacterial Properties |
| title_sort | electrospun pcl filtration membranes enhanced with an electrosprayed lignin coating to control wettability and anti bacterial properties |
| topic | electrospinning electrospraying lignin oak eucalyptus PCL |
| url | https://www.mdpi.com/2073-4360/16/5/674 |
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