Self-patterning processes originated by physical stimuli have been extensively documented in thin films, whereas spontaneous wrinkling phenomena due to chemical transformation processes are, to the best of our knowledge, unprecedented. Herein we report a case of spontaneous polymerization-driven surface nano-patterning (B500 nm) that develops in smooth thin solid films of 5,6-dihydroxyindole (DHI), a major precursor of eumelanin polymers, over a time scale of 30 to 60 days in air at room temperature. The phenomenon can be observed only above a critical film thickness of B250 nm and it is affected by exposure to ammonia vapors causing acceleration of the oxidation process. The thickness-dependent onset of wrinkling can be attributed to non-homogeneous rates of oxidation through the film causing slow swelling/expansion of the inner layers followed by fast stiffening and cross-linking in the outer layer exposed to higher oxygen levels.

Spontaneous wrinkle emergence in nascent eumelanin thin films / Oscurato, STEFANO LUIGI; Formisano, Fabio; DE LISIO, Corrado; D’Ischia, Marco; Gesuele, Felice; Maddalena, Pasqualino; Manini, Paola; Migliaccio, Ludovico; Pezzella, Alessandro. - In: SOFT MATTER. - ISSN 1744-6848. - 15:45(2019), pp. 9261-9270. [10.1039/c9sm01885a]

Spontaneous wrinkle emergence in nascent eumelanin thin films

Stefano Luigi Oscurato
Membro del Collaboration Group
;
FORMISANO, FABIO
Membro del Collaboration Group
;
Corrado de Lisio
Membro del Collaboration Group
;
Marco d’Ischia
Membro del Collaboration Group
;
Felice Gesuele
Membro del Collaboration Group
;
Pasqualino Maddalena
Membro del Collaboration Group
;
Paola Manini
Membro del Collaboration Group
;
Ludovico Migliaccio
Membro del Collaboration Group
;
Alessandro Pezzella
Membro del Collaboration Group
2019

Abstract

Self-patterning processes originated by physical stimuli have been extensively documented in thin films, whereas spontaneous wrinkling phenomena due to chemical transformation processes are, to the best of our knowledge, unprecedented. Herein we report a case of spontaneous polymerization-driven surface nano-patterning (B500 nm) that develops in smooth thin solid films of 5,6-dihydroxyindole (DHI), a major precursor of eumelanin polymers, over a time scale of 30 to 60 days in air at room temperature. The phenomenon can be observed only above a critical film thickness of B250 nm and it is affected by exposure to ammonia vapors causing acceleration of the oxidation process. The thickness-dependent onset of wrinkling can be attributed to non-homogeneous rates of oxidation through the film causing slow swelling/expansion of the inner layers followed by fast stiffening and cross-linking in the outer layer exposed to higher oxygen levels.
2019
Spontaneous wrinkle emergence in nascent eumelanin thin films / Oscurato, STEFANO LUIGI; Formisano, Fabio; DE LISIO, Corrado; D’Ischia, Marco; Gesuele, Felice; Maddalena, Pasqualino; Manini, Paola; Migliaccio, Ludovico; Pezzella, Alessandro. - In: SOFT MATTER. - ISSN 1744-6848. - 15:45(2019), pp. 9261-9270. [10.1039/c9sm01885a]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11588/775112
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