Marangoni Instability Driven Surface Relief Grating in an Azobenzene-Containing Polymer Film

Kim, Chae Bin; Wistrom, James C.; Ha, Heonjoo; Zhou, Sunshine X.; Katsumata, Reika; Jones, Amanda; Janes, Dustin W.; Miller, Kevin M.; Ellison, Christopher J.

doi:10.1021/acs.macromol.6b01848

Cited by 44 publications

(35 citation statements)

References 61 publications

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“…Thus, PAz in the cis-rich state has a higher surface tension than that in the trans state. These results agree with the reports by Ellison et al 36 for the surface fabrication by photopatterning onto an Az polymer and our observations in inkjet printed system 40 . The effect of linear UV light polarisation was examined.…”

Section: Resultssupporting

confidence: 94%

“…These results are well understood by the Marangoni flow driven by the light-triggered surface tension instability. Although only a few previous reports mentioned the significance of the surface effect 57,58 , several recent studies emphasised the importance of surface proximities for both LC 40,58 and amorphous 17,18,36,57 polymers. To precisely understand the behaviour, the driving mechanism, including the surface effect, should be reconsidered.…”

Section: Resultsmentioning

confidence: 99%

“…For these films, photoirradiation induces multiple changes simultaneously such as a viscosity change, molecular order and orientation change, and surface tension change. Kim et al 36 showed the surface fabrication of an Az polymer via the Marangoni flow, but these other factors may also be involved.…”

Section: Srg Film Essentially Without Colourmentioning

confidence: 99%

“…Their model stressed enhanced molecular diffusion in proximity of the free surface. Ellison et al 36 – 39 have proposed microfabrications via the Marangoni flow by photochemical reactions. Similarly, we reported UV light-induced mass transfer of an Az-containing SCLCP film at the inkjet-printed lines of another polymer 40 .…”

Section: Introductionmentioning

confidence: 99%

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Photo-triggered large mass transport driven only by a photoresponsive surface skin layer

Kitamura

Kato

Berk

et al. 2020

Sci Rep

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Since the discovery 25 years ago, many investigations have reported light-induced macroscopic mass migration of azobenzene-containing polymer films. Various mechanisms have been proposed to account for these motions. This study explores light-inert side chain liquid crystalline polymer (SCLCP) films with a photoresponsive polymer only at the free surface and reports the key effects of the topmost surface to generate surface relief gratings (SRGs) for SCLCP films. The top-coating with an azobenzene-containing SCLCP is achieved by the Langmuir-Schaefer (LS) method or surface segregation. A negligible amount of the photoresponsive skin layer can induce large SRGs upon patterned UV light irradiation. Conversely, the motion of the SRG-forming azobenzene SCLCP is impeded by the existence of a LS monolayer of the octadecyl side chain polymer on the top. These results are well understood by considering the Marangoni flow driven by the surface tension instability. This approach should pave the way toward in-situ inscription of the surface topography for light-inert materials and eliminate the strong light absorption of azobenzene, which is a drawback in optical device applications. Surface morphology generations on azobenzene(Az)-containing polymer films induced by patterned irradiation have been the active area in photofunctional material research. In 1995, Natansohn's 1 and Tripathy's 2 groups independently reported the induction of surface relief gratings (SRGs) on Az amorphous films using interference irradiation of two laser beams. Since then, photoinduced SRG processes have been reported using various photofunctional materials such as amorphous polymers 1-20 , side chain liquid crystalline polymers (SCLCPs) 21-27 , supramolecular systems 24,27-29 , amorphous molecular materials 30. Additionally, SRG formation can be realised using other photoresponsive units 31-35. Various mechanistic models for mass transfer have been proposed: isomerisation pressure due to volume change 7,8 , gradient force 9-11 , mean-field model 12 , directed softening or fluidisation 13-15 , molecular diffusion 16-18,34 , molecular orientation force 19,20 , etc. With regard to Az-containing SCLCPs 21-27 , UV light irradiation leads to a photochemical phase transition between the liquid crystal (LC) and isotropic phases. This phase change plays an important role in highly efficient SRG formation 23,25,26 , which requires an overall dose of much less than 1 J cm-2. Typically mass transport depends on the light irradiation conditions and physicochemical properties. Consequently, a universal explanation about the mechanism has yet to be provided. Recent studies have noted the importance of the surface effect on the mass transfer process. Ambrosio et al. 17,18 proposed an anisotropic light-driven molecular diffusion model for spiral morphology induction under vortexbeam illumination. Their model stressed enhanced molecular diffusion in proximity of the free surface. Ellison et al. 36-39 have proposed microfabrications via the Marangoni flow by photo...

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Section: Resultssupporting

confidence: 94%

Section: Resultsmentioning

confidence: 99%

Section: Srg Film Essentially Without Colourmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Photo-triggered large mass transport driven only by a photoresponsive surface skin layer

Kitamura

Kato

Berk

et al. 2020

Sci Rep

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“…Hence, in the course of this process, the ATSP oligomer molecules were relocated, driven by the effective capillary forces on site, inside the bulges. The oligomer molecules thereby were adsorbed on the spot forming periodically located concentrated particle sites . Then, through the cure reaction of the ATSP, an epitaxial growth mechanism proceeded.…”

Section: Resultsmentioning

confidence: 99%

Periodic Functionalization of Graphene‐Layered Alumina Nanofibers with Aromatic Thermosetting Copolyester via Epitaxial Step‐Growth Polymerization

Bakır

Meyer

Hussainova

et al. 2017

Macro Chemistry & Physics

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In situ epitaxial step‐growth polymerization driven interfacial functionalization of aromatic thermosetting copolyester (ATSP) with multilayered graphene wrapped alumina nanofiber surface is reported. During a thermal condensation polymerization, ATSP dip‐coated fiber strands develop a nanohybrid shish–kebab structure with periodically assembled and off‐surface grown micrometer‐scale lamella ATSP domains. A mechanism combining the Plateau–Rayleigh instability, the Marangoni effect, and the epitaxial growth phenomena is proposed to elucidate controlling parameters in the process. X‐ray diffraction measurements clearly demonstrate the formation of a mesomorphic lamella phase not present within either the neat ATSP or pristine fiber samples. Results of solid‐state nuclear magnetic resonance and thermogravimetric analysis reveal the development of an interfacial coupling between the graphene‐coated ceramic nanofibers and the ATSP matrix.

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Assembly‐Induced Dynamic Structural Color in a Host‐Guest System for Time‐Dependent Anticounterfeiting and Double‐Lock Encryption

Ji,

Song,

2024

Angewandte Chemie

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Manipulation of periodic micro/nanostructures in polymer film is of great importance for academics and industrial applications in anticounterfeiting. However, with the increasing demand on information security, materials with time‐dependent features are urgently required, especially the material where the same information can appear more than once on the time scale. Here, one concise strategy to realize time‐dependent anticounterfeiting and “double‐lock” information encryption based on a host‐guest system is proposed, with one photoresponsive azopolymer as the host and one liquid‐crystalline molecule as the guest. The system exhibits a tunable mass transport in pre‐designed periodic micro/nanostructures by tailoring the process of cis‐to‐trans recovery of azo groups and assembly of mesogenic trans‐isomers, resulting in a dynamic structural color in film. Taking advantage of this extraordinary feature, time‐dependent dynamic anticounterfeiting has been achieved. More importantly, the time of each state’s appearance in the whole process can be modulated by changing the host‐guest ratio. Combining the manipulatable process of mass transport with the unique decoding method, the stored information in film can be decrypted correctly. This work provides an unprecedented dynamic approach for advanced anticounterfeiting technology with a higher level of security and high‐end applications in information encryption.

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Marangoni Instability Driven Surface Relief Grating in an Azobenzene-Containing Polymer Film

Cited by 44 publications

References 61 publications

Photo-triggered large mass transport driven only by a photoresponsive surface skin layer

Photo-triggered large mass transport driven only by a photoresponsive surface skin layer

Periodic Functionalization of Graphene‐Layered Alumina Nanofibers with Aromatic Thermosetting Copolyester via Epitaxial Step‐Growth Polymerization

Assembly‐Induced Dynamic Structural Color in a Host‐Guest System for Time‐Dependent Anticounterfeiting and Double‐Lock Encryption

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