Direct observation of athermal photofluidisation in azo-polymer films

Hurduc, Nicolae, Donose, Bogdan C., Macovei, Alina, Paius, Cristina, Ibanescu, Constanta, Scutaru, Dan, Hamel, Matthieu, Nichita-Branza, Norica and Rocha, Licinio (2014) Direct observation of athermal photofluidisation in azo-polymer films. Soft Matter, 10 26: 4640-4647. doi:10.1039/C4SM00397G

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Author Hurduc, Nicolae
Donose, Bogdan C.
Macovei, Alina
Paius, Cristina
Ibanescu, Constanta
Scutaru, Dan
Hamel, Matthieu
Nichita-Branza, Norica
Rocha, Licinio
Title Direct observation of athermal photofluidisation in azo-polymer films
Journal name Soft Matter   Check publisher's open access policy
ISSN 1744-683X
1744-6848
Publication date 2014-07-14
Year available 2014
Sub-type Article (original research)
DOI 10.1039/C4SM00397G
Open Access Status Not Open Access
Volume 10
Issue 26
Start page 4640
End page 4647
Total pages 8
Place of publication Cambridge, United Kingdom
Publisher Royal Society of Chemistry
Language eng
Abstract The surface relief gratings (SRGs) can be generated when azo-polymer films are exposed to laser beam interference as a result of mass migration. Despite considerable research effort over the past two decades this complex phenomenon remains incompletely understood. Here we show, for the first time, the athermal photofluidisation of azo-polysiloxane films exposed to 488 nm light, directly monitored by optical microscopy. A process of surface relief erasure occurring in parallel with its inscription was also observed during laser irradiation. We therefore propose a new mechanism of SRG formation, based on three different processes: (1) the polymer photo-fluidization in illuminated regions, (2) the mass displacement from illuminated to dark regions and (3) the inverse mass displacement, from dark to illuminated regions. The mechanical properties of the films during UV light irradiation were investigated by classical rheology and, for the first time, by using amplitude modulation-frequency modulation atomic force microscopy (AM-FM AFM).
Formatted abstract
The surface relief gratings (SRGs) can be generated when azo-polymer films are exposed to laser beams interference as a result of mass migration. Despite considerable research effort over the past two decades this complex phenomenon remains incompletely understood. Here we show, in premiere, the athermal photofluidisation of azo-polysiloxane films exposed to 488 nm light, directly monitored by optical microscopy. A process of surface relief erasure occurring in parallel with its inscription was also observed during laser irradiation. We therefore propose a new mechanism of SRG formation, based on three different processes: (1) the polymer photo-fluidization in the illuminated regions (2) the mass displacement from illuminated to dark regions and (3) the inverse mass displacement, from dark to illuminated regions. The mechanical properties of the films during UV light irradiation were investigated by classical rheology and, in premiere, by using amplitude modulation-frequency modulation atomic force microscopy (AM-FM AFM).

Light induced fluidization of azopolysiloxane: exposure to 488 nm light generates instantaneous mass transfer as result of trans-cis isomerization in unsubstituted azophenol polymers. p-Nitro azophenol in the side chain is responsible for the suppression of athermal photofluidization. Viscoelastic mapping confirms the changes of rheological properties upon exposure to 365 nm light.
Keyword Chemistry, Multidisciplinary
Chemistry
CHEMISTRY, MULTIDISCIPLINARY
Q-Index Code C1
Q-Index Status Confirmed Code
Grant ID CEA-C1-01/2010
Institutional Status UQ
Additional Notes First published online: 10 April 2014.

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2015 Collection
Advanced Water Management Centre Publications
 
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Created: Sun, 13 Apr 2014, 17:50:20 EST by Dr Bogdan Donose on behalf of Advanced Water Management Centre