Computer-generated holograms for complex surface reliefs on azopolymer films

Oscurato, Stefano Luigi; Salvatore, Marcella; Borbone, Fabio; Maddalena, Pasqualino; Ambrosio, Antonio

doi:10.1038/s41598-019-43256-w

Cited by 36 publications

(35 citation statements)

References 38 publications

(37 reference statements)

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“…Superficial azopolymer textures with degree of complexity higher than simple sinusoidal modulations are usually achieved by acting on the preparation of pre‐patterned azopolymer surfaces, which can be subsequently directionally reconfigured under light irradiation, [ 48,49,32 ] or by using complex spatially structured intensity illuminations, as we recently demonstrated exploiting the possibility offered by a digital holographic illumination setup [ 50 ] for the realization of almost arbitrary 2D relief shapes. [ 51 ]…”

Section: Introductionmentioning

confidence: 99%

Deterministic Realization of Quasicrystal Surface Relief Gratings on Thin Azopolymer Films

Salvatore

Borbone

Oscurato

2020

Adv Materials Inter

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Spatially structured UV–visible light fields generate topographic modulations on the surface of films of azobenzene‐containing polymers. The geometry of the surface reliefs depends on the spatiotemporal distribution of light over the sample. If multistep sequential irradiations are used, even illumination configurations as simple as the interference of two linearly polarized beams produce complex surface textures. This is the case of the quasicrystal geometries, obtainable as the superposition of multiple sinusoidal surface relief gratings oriented in different directions over the surface. The quantitative relief design would require a comprehensive theoretical description of the light‐induced relief formation mechanism, which is still elusive for azopolymers. Here, despite limiting the description at a phenomenological level, the deterministic design of the quasicrystal surface reliefs obtained in sequential light exposures of an azopolymer film is demonstrated. The model provides an excellent agreement between simulated and experimental relief textures, predicting also the dependence of relief structural features on illumination parameters as the number of exposure steps and the beam interference angle. The deterministic texture design allows the controlled tailoring of surface functionalities related to the relief geometry like light diffraction properties of the samples, which are here exploited to manipulate, split, and trap diffracted light.

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Section: Introductionmentioning

confidence: 99%

Deterministic Realization of Quasicrystal Surface Relief Gratings on Thin Azopolymer Films

Salvatore

Borbone

Oscurato

2020

Adv Materials Inter

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“…The photo-patterning abilities of the azopolymer used in the present work and the dependence of the light-induced surface reliefs on the intensity and polarization distribution of irradiated light field have been extensively investigated in several previous papers [12,14,16,30].…”

Section: Azopolymer and Film Preparationmentioning

confidence: 99%

“…The consequence of this molecular light-fueled material motion is the macroscopic structuration of azopolymer films and microvolumes, whose geometry depends on the intensity and polarization distributions of the irradiated light field [11][12][13][14][15]. Consequently, azopolymers can be directly structured over large scales with high quality, in spatially selective, simple, and cost-effective way, creating spatially ordered and even complex [16] topological patterns exploitable as microstructured platforms to control cellular orientation and migration in in vitro cultures [17,18]. Additionally, due to the non-destructive nature of the light-induced mass migration phenomenon, the structuration of the azopolymers is reversible [19].…”

Section: Introductionmentioning

confidence: 99%

“…This feature permits the peculiar possibility of repeatedly changing the topography of the surface through light irradiation, ideally allowing even the remotely real-time variation of topographic stimuli, which can be crucial for applications in biomedical fields [20]. Moreover, the use of the azobenzene-containing polymers as substrates for cell guidance and ECM mimicking can take advantage also of the reversible switch of their electric properties produced, simultaneously to the macroscopic mass displacement, by the photo-orientation of the azobenzene molecules under illumination [16,21]. This effect can indeed enhance the conjugation of polymeric chains [22][23][24], increasing the charge carrier mobility and the ionic conductivity in aqueous solutions.…”

Section: Introductionmentioning

confidence: 99%

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Quantitative Study of Morphological Features of Stem Cells onto Photopatterned Azopolymer Films

Salvatore

Oscurato

D’Albore

et al. 2020

JFB

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In the last decade, the use of photolithography for the fabrication of structured substrates with controlled morphological patterns that are able to interact with cells at micrometric and nanometric size scales is strongly growing. A promising simple and versatile microfabrication method is based on the physical mass transport induced by visible light in photosensitive azobenzene-containing polymers (or azopolymers). Such light-driven material transport produces a modulation of the surface of the azopolymer film, whose geometry is controlled by the intensity and the polarization distributions of the irradiated light. Herein, two anisotropic structured azopolymer films have been used as substrates to evaluate the effects of topological signals on the in vitro response of human mesenchymal stem cells (hMSCs). The light-induced substrate patterns consist of parallel microgrooves, which are produced in a spatially confined or over large-scale areas of the samples, respectively. The analysis of confocal optical images of the in vitro hMSC cells grown on the patterned films offered relevant information about cell morphology—i.e., nuclei deformation and actin filaments elongation—in relation to the geometry and the spatial extent of the structured area of substrates. The results, together with the possibility of simple, versatile, and cost-effective light-induced structuration of azopolymers, promise the successful use of these materials as anisotropic platforms to study the cell guidance mechanisms governing in vitro tissue formation.

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“…Meanwhile, one is required to consider many aspects of computer graphics, such as lighting, viewing positions, materials and structures, and how the light interacts with the materials. [19][20][21][22] In this article, we propose an integrated finite element and computer imaging (FEM-CI) method to generate scratches and produce realistic images of the scratches. Finite element modeling of scratching is performed on a rough surface with a wide range of microgeometries.…”

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confidence: 99%

An attempt to simulate structure and realistic images of scratches on rough polymeric surfaces

Gao

Wang

Coffey

et al. 2020

Journal of Polymer Science

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Numerical simulation of scratching has been shown to exhibit many advantages in material development and surface design and can provide detailed information associated with the scratch structure. However, the visual appearance of simulated scratches in real-world scenarios has seldom been studied. This study simulates the structure and visual appearance of scratches on rough polymer surfaces by combining the finite element method (FEM) with computer imaging (CI) techniques. FEM modeling of scratching incorporates a wide range of microgeometries in rough surfaces to ensure that the resulting scratch surfaces contain all features, regardless of whether they are visible to the human eye. Computer graphics produce realistic images of numeric scratch surfaces in real-world lighting conditions. This method demonstrates the advantages of easily simulating scratches on rough surfaces and assessing both abrasion strength and visual scratch resistance. Scratch tests on commercial polymer surfaces at different scratch forces demonstrate that the method can satisfactorily predict the structures and scales of scratches. The simulated images correlate closely with camera-acquired photographs in terms of the visual appearance of scratch surfaces, effect of lighting conditions, and dependence of the visual width of scratches on the scratching force, material, pigment, and additive in the material.

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Computer-generated holograms for complex surface reliefs on azopolymer films

Cited by 36 publications

References 38 publications

Deterministic Realization of Quasicrystal Surface Relief Gratings on Thin Azopolymer Films

Deterministic Realization of Quasicrystal Surface Relief Gratings on Thin Azopolymer Films

Quantitative Study of Morphological Features of Stem Cells onto Photopatterned Azopolymer Films

An attempt to simulate structure and realistic images of scratches on rough polymeric surfaces

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