Light induced conch-shaped relief in an azo-polymer film.
Ontology highlight
ABSTRACT:
SUBMITTER: Watabe M
PROVIDER: S-EPMC3945491 | biostudies-other | 2014
REPOSITORIES: biostudies-other
Similar Datasets
Project description:The isomerisation of azo dyes can induce conformational changes which have potential applications in medicine and environmental protection. We developed an agar diffusion assay to test the capture and release of biologically active molecules from an azo electro-optic polymer, Poly (Disperse Red 1 methacrylate) (DR1/PMMA). The assay monitors the growth of bacteria placed in soft agar under a glass coverslip. Antibiotics can then be applied on the coverslip resulting in the clearance of the area under the coverslip due to growth inhibition. This assay demonstrates that DR1/PMMA is able to capture either tetracycline or ampicillin and the relative amount of DR1/PMMA required for capture was determined. Finally, the active antibiotics can be released from DR1/PMMA by exposure to green laser light. Exposure to white light from a torch or to heat does not release the antibiotic.
| S-EPMC7039927 | biostudies-literature
Project description:When an azobenzene-containing polymer film is exposed to non-uniform illumination, a light-induced mass migration process may be induced, leading to the formation of relief patterns on the polymer-free surface. Despite many years of research effort, several aspects of this phenomenon remain poorly understood. Here we report the appearance of spiral-shaped relief patterns on the polymer film under the illumination of focused Laguerre-Gauss beams with helical wavefronts and an optical vortex at their axis. The induced spiral reliefs are sensitive to the vortex topological charge and to the wavefront handedness. These findings are unexpected because the doughnut-shaped intensity profile of Laguerre-Gauss beams contains no information about the wavefront handedness. We propose a model that explains the main features of this phenomenon through the surface-mediated interference of the longitudinal and transverse components of the optical field. These results may find applications in optical nanolithography and optical-field nanoimaging.
| S-EPMC3432464 | biostudies-literature
Project description:Achieving oscillatory motion in polymers without requiring on/off switching of stimuli is a current challenge. Hereby, a free-standing liquid crystal polymer (LCP) is demonstrated to undergo a sustained oscillatory motion when triggered by light, moving back and forth, resembling the motion of a rocking-chair. Two polymer films having different azobenzene photo-switches have been studied, revealing photoswitch requirements as well as illumination conditions necessary to sustain oscillations. The motion presented here shows how feedback loops involving light-triggered actuation, self-shadowing and a shifting center of gravity can be utilized to achieve self-sustained motion in free-standing polymers.
| S-EPMC7646255 | biostudies-literature
Project description:In this work, we study the light-induced changes of the rotational speed of a thin photomobile film using a single-axis acoustic levitator operating at 40 kHz. In our experiments, a 50 μm thick photomobile polymer film (PMP) is placed in one of the nodes of a stationary acoustic field. Under the action of the field, the film remains suspended in air. By externally perturbing this stable equilibrium condition, the film begins to rotate with its natural frequency. The rotations are detected in real time by monitoring the light of a low power He-Ne laser impinging on and reflected by the film itself. During the rotational motion, an external laser source is used to illuminate the PMP film; as a consequence, the film bends and the rotational speed changes by about 20 Hz. This kind of contactless long-distance interaction is an ideal platform for the development and study of many electro-optics devices in microgravity and low-friction conditions. In particular, we believe that this technology could find applications in research fields such as 3D dynamic displays and aerospace applications.
| S-EPMC9860897 | biostudies-literature
Project description:Rectangular wave-shaped surface-relief plasmonic gratings (RSR-PGs) have been fabricated from a hybrid polymer by employing a simple nanoimprint photocuring lithography technique using a silicon template, followed by gold nanolayer metallization on top of the formed replica structure. By forming a one-dimensional (1D) plasmonic grating with a periodicity of approximately 700 nm, a reflectance spectral dip was experimentally observed in the visible light region, from 600 to 700 nm, with increasing incident angle from 45° to 60°. This dip can be associated with surface plasmon resonance (SPR) wave excitation, which is coupled with the diffraction order m = - 2. The calculations of reflectance spectra simulation using the rigorous coupled wave analysis (RCWA) method have also been carried out, resulting in the appearance of an SPR dip in the range of 600-700 nm, for incident angles in the range of 45°-65°, which agrees with the experimental results. Interestingly, these RSR-PGs show richer plasmon characteristics than the sine-wave-shaped plasmonic gratings. The experimental and spectral simulation results revealed two different plasmonic excitation modes: long-range SPR and quasi-localized SPR (LSPR). While the long-range SPR was formed above the ridge sections along the grating structure surface, the quasi-localized SPR was locally formed inside the groove. In addition, for RSR-PGs with a narrow groove section, the long-range SPR seems to be coupled with the periodic structure of the grating, resulting in the appearance of plasmonic lattice surface resonance (LSR) that is indicated by a narrower plasmon resonance dip. These characteristics are quite different from those found in the sine wave-shaped plasmonic gratings. The present results may thus provide better insights for understanding the plasmon excitations in this type of rectangular plasmonic grating and might be useful for designing their structure for certain practical applications.
| S-EPMC10066186 | biostudies-literature
Project description:This paper describes a synthetic approach for photocrosslinkable polyfluorene (pc-PFO) semiconducting polymer dots, and demonstrates their superior ability to crosslink and form 3-D intermolecular polymer networks. The crosslinked pc-PFO Pdots are equipped with excellent encapsulating ability of functional small molecules. Optimum conditions of light irradiation on pc-PFO Pdots were investigated and clarified by using polymer thin films as a model. By employing the optimal light irradiation conditions, we successfully crosslinked pc-PFO Pdots and studied their particle sizes, photophysical, and colloidal properties. Single-particle imaging and dynamic-light-scattering measurements were conducted to understand the behaviors of photocrosslinked Pdots. Our results indicate pc-PFO Pdots can be easily photocrosslinked and the crosslinked species have excellent colloidal stability, physical and chemical stability, fluorescence brightness, and specific binding properties for cellular labeling. Considering that optical stimulus can work remotely, cleanly, and non-invasively, this study should pave the way for a promising approach to further develop stimuli-responsive ultrabright and versatile Pdot probes for biomedical imaging.
| S-EPMC4335711 | biostudies-literature
Project description:Nanoparticles with unconventional shapes may exhibit different types of assembly architectures that depend critically on the environmental conditions under which they are formed. Here, we demonstrate how the presence of polymer (polymethyl methacrylate, PMMA) molecules in a solution, in which CdSe(core)/CdS(pods) octapods are initially dispersed, affects the octapod-polymer organization upon solvent evaporation. We show that a fast drop-drying process can induce a remarkable two-dimensional (2D) self-assembly of octapods at the polymer/air interface. In the resulting structure, each octapod is oriented like a "ballerina", that is, only one pod sticks out of the polymer film and is perpendicular to the polymer-air interface, while the opposite pod (with respect to the octapod's center) is fully immersed in the film and points toward the substrate, like a ballerina performing a grand battement. In some areas, a hexagonal-like pattern is formed by the ballerinas in which the six nonvertical pods, which are all embedded in the film, maintain a pod-pod parallel configuration with respect to neighboring particles. We hypothesize that the mechanism responsible for such a self-assembly is based on a fast adsorption of the octapods from bulk solution to the droplet/air interface during the early stages of solvent evaporation. At this interface, the octapods maintain enough rotational freedom to organize mutually in a pod-pod parallel configuration between neighboring octapods. As the solvent evaporates, the octapods form a ballerina-rich octapod-polymer composite in which the octapods are in close contact with the substrate. Finally, we found that the resulting octapod-polymer composite is less hydrophilic than the polymer-only film.
| S-EPMC3924848 | biostudies-literature
Project description:Free-form factor optoelectronics is becoming more important for various applications. Specifically, flexible and transparent optoelectronics offers the potential to be adopted in wearable devices in displays, solar cells, or biomedical applications. However, current transparent electrodes are limited in conductivity and flexibility. This study aims to address these challenges and explore potential solutions. For the next-generation transparent conductive electrode, Al-doped zinc oxide (AZO) and silver (AZO/Ag/AZO) deposited by in-line magnetron sputtering without thermal treatment was investigated, and this transparent electrode was used as a transparent organic light-emitting diode (OLED) anode to maximize the transparency characteristics. The experiment and simulation involved adjusting the thickness of Ag and AZO and OLED structure to enhance the transmittance and device performance. The AZO/Ag/AZO with Ag of 12 nm and AZO of 32 nm thickness achieved the results of the highest figure of merit (FOM) (Φ550 = 4.65 mΩ-1) and lowest roughness. The full structure of transparent OLED (TrOLED) with AZO/Ag/AZO anode and Mg:Ag cathode reached 64.84% transmittance at 550 nm, and 300 cd/m2 at about 4 V. The results demonstrate the feasibility of adopting flexible substrates, such as PET, without the need for thermal treatment. This research provides valuable insights into the development of transparent and flexible electronic devices.
| S-EPMC10818506 | biostudies-literature
Project description:In this paper we report on photoswitchable polymer surfaces with dynamically and reversibly fluctuating topographies. It is well known that when azobenzene containing polymer films are irradiated with optical interference patterns the film topography changes to form a surface relief grating. In the simplest case, the film shape mimics the intensity distribution and deforms into a wave like, sinusoidal manner with amplitude that may be as large as the film thickness. This process takes place in the glassy state without photo-induced softening. Here we report on an intriguing discovery regarding the formation of reliefs under special illumination conditions. We have developed a novel setup combining the optical part for creating interference patterns, an AFM for in situ acquisition of topography changes and diffraction efficiency signal measurements. In this way we demonstrate that these gratings can be "set in motion" like water waves or dunes in the desert. We achieve this by applying repetitive polarization changes to the incoming interference pattern. Such light responsive surfaces represent the prerequisite for providing practical applications ranging from conveyer or transport systems for adsorbed liquid objects and colloidal particles to generation of adaptive and dynamic optical devices.
| S-EPMC9065545 | biostudies-literature
Project description:Stretching a polymer film induces a conformational change (from the twisted to planar state) in the embedded porphyrin dimer, as evidenced by steady-state and time-resolved emission spectra.
| S-EPMC6167131 | biostudies-literature