Novel approaches for fabricating safe- and sustainable-by-design coatings are being studied to replace perfluorooctanoic acid or other fluorinated substances that are raising concerns for their potential hazard for human health [1]. In this study, a chitosan-based coating with modified functionality is developed through a solvent-free deposition method. The chitosan backbone is modified with fatty acid side groups to change the polymer wettability from hydrophilic to hydrophobic [2]. The effective chitosan functionality modification with stearoyl groups is assessed and confirmed via combined by 1H and 13C DD-MAS Solid State NMR, FTIR and TGA analysis. The modified chitosan is then deposited by a solvent-free approach consisting of: i) freeze-drying, which allow safe long-term storage, ii) sieving, iii) thermal treatment (Figure 1a). Controlling the amount of deposited coating, transparency and superhydrophobicity can be tuned based on the desired characteristics. A superhydrophobic wetting state (θA = 150°, θR = 144°) is reached for coating amount of 4.8 mg/cm2, obtaining an opaque surface, whereas for lower amount of 0.8 mg/cm2, the coating is hydrophobic (θA = 108°, θR = 67°) with very good transparency (Figure 1b). A morphological characterization by SEM and optical microscope analyses of the coating provides evidence of increased roughness along with increased hydrophobicity. Our innovative and sustainable deposition method for modified chitosan is a simple procedure for creating bio-based transparent hydrophobic coatings, which is fluorine-free and does not require any solvent during deposition. As an outlook, we envision a further development of coatings to better control surface topography to decrease scattering and increase transmittance, and mechanical durability improvement using adhesion promoters or cross-linkers.

Tagliaro, I., Seccia, S., Pellegrini, B., Bertini, S., Antonini, C. (2022). Tunable transparency and superhydrophobicity of chitosan-based fluorine-free coatings. Intervento presentato a: ISPAC International Symposium on Polymer Analysis and Characterization, Milano, Italia.

Tunable transparency and superhydrophobicity of chitosan-based fluorine-free coatings

Irene Tagliaro
Primo
;
Stefano Seccia;Beatrice Pellegrini;Carlo Antonini
Ultimo
2022

Abstract

Novel approaches for fabricating safe- and sustainable-by-design coatings are being studied to replace perfluorooctanoic acid or other fluorinated substances that are raising concerns for their potential hazard for human health [1]. In this study, a chitosan-based coating with modified functionality is developed through a solvent-free deposition method. The chitosan backbone is modified with fatty acid side groups to change the polymer wettability from hydrophilic to hydrophobic [2]. The effective chitosan functionality modification with stearoyl groups is assessed and confirmed via combined by 1H and 13C DD-MAS Solid State NMR, FTIR and TGA analysis. The modified chitosan is then deposited by a solvent-free approach consisting of: i) freeze-drying, which allow safe long-term storage, ii) sieving, iii) thermal treatment (Figure 1a). Controlling the amount of deposited coating, transparency and superhydrophobicity can be tuned based on the desired characteristics. A superhydrophobic wetting state (θA = 150°, θR = 144°) is reached for coating amount of 4.8 mg/cm2, obtaining an opaque surface, whereas for lower amount of 0.8 mg/cm2, the coating is hydrophobic (θA = 108°, θR = 67°) with very good transparency (Figure 1b). A morphological characterization by SEM and optical microscope analyses of the coating provides evidence of increased roughness along with increased hydrophobicity. Our innovative and sustainable deposition method for modified chitosan is a simple procedure for creating bio-based transparent hydrophobic coatings, which is fluorine-free and does not require any solvent during deposition. As an outlook, we envision a further development of coatings to better control surface topography to decrease scattering and increase transmittance, and mechanical durability improvement using adhesion promoters or cross-linkers.
No
relazione (orale)
chitosan, wetting, superhydrophobic
English
ISPAC International Symposium on Polymer Analysis and Characterization
Tagliaro, I., Seccia, S., Pellegrini, B., Bertini, S., Antonini, C. (2022). Tunable transparency and superhydrophobicity of chitosan-based fluorine-free coatings. Intervento presentato a: ISPAC International Symposium on Polymer Analysis and Characterization, Milano, Italia.
Tagliaro, I; Seccia, S; Pellegrini, B; Bertini, S; Antonini, C
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/398267
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