The capability to pattern polymer surfaces at different length scales is an important goal in different research fields, including display technologies, microelectronics, optics, as well as biorelated and medical science. However, the ability to optically and dynamically manipulate topography is a key feature enabling remote control of associated effects/processes mediated by the surface. Azopolymers are largely investigated to this aim based on their sensitivity to optical fields and reconfigurability capabilities. In this work, surface relief formation induced by polarization patterns on an amorphous azopolymer structurally engineered to have large photoinduced birefringence has been investigated both experimentally and theoretically. Based on the different light polarization patterns, depth and shape of the relief grating can be controlled. An optically induced gradient force model that includes both the spatial distribution and the anisotropy of the material permittivity has been theoretically analyzed. The proposed approach is able to explain the experimental results and to overcome the limitation of existing models.
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http://dx.doi.org/10.1021/acsami.9b12624 | DOI Listing |
Acta Crystallogr B Struct Sci Cryst Eng Mater
February 2025
Novosibirsk State University, Pirogova 1, Novosibirsk 630090, Russian Federation.
High-pressure and low-temperature structural changes in the ferroelectric phase of (R)-3-quinuclidinol are analysed. The changes in unit-cell volume and parameters are continuous both on cooling and under increasing pressure. The anisotropy of the structural strain, however, is found to be different.
View Article and Find Full Text PDFACS Nano
January 2025
Department of Mechanical Engineering, University of California at Riverside, Riverside, California 92521, United States.
Sensing light's polarization and wavefront direction enables surface curvature assessment, material identification, shadow differentiation, and improved image quality in turbid environments. Traditional polarization cameras utilize multiple sensor measurements per pixel and polarization-filtering optics, which result in reduced image resolution. We propose a nanophotonic pipeline that enables compressive sensing and reduces the sampling requirements with a low-refractive-index, self-assembled optical encoder.
View Article and Find Full Text PDFJ Cell Biol
April 2025
Department of Physics and Astronomy, University of Denver, Denver, CO, USA.
In the early Drosophila embryo, germband elongation is driven by oriented cell intercalation through t1 transitions, where vertical (dorsal-ventral aligned) interfaces contract and then resolve into new horizontal (anterior-posterior aligned) interfaces. Here, we show that contractile events produce a continuous "rectification" of cell interfaces, in which interfaces systematically rotate toward more vertical orientations. As interfaces rotate, their behavior transitions from elongating to contractile regimes, indicating that the planar polarized identities of cell-cell interfaces are continuously re-interpreted in time depending on their orientation angle.
View Article and Find Full Text PDFSmall
January 2025
Key Laboratory of Aerospace Materials and Performance (Ministry of Education) School of Materials Science and Engineering, Beihang University, No.37 Xueyuan Road, Beijing, 100191, P. R. China.
A reasonable construction of hollow structures to obtain high-performance absorbers is widely studied, but it is still a challenge to select suitable materials to improve the low-frequency attenuation performance. Here, the FeO@C@NiO nanoprisms with unique tip shapes, asymmetric multi-path hollow cavity, and core-shell heteroepitaxy structure are designed and synthesized based on anisotropy and intrinsic physical characteristics. Impressively, by changing the load of NiO, the composites achieve strong absorption, broadband, low-frequency absorption: the reflection loss of -55.
View Article and Find Full Text PDFAdv Sci (Weinh)
January 2025
School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China.
The past decade witnessed a surge in discoveries where biological systems, such as bacteria or living cells, inherently portray active polar or nematic behavior: they prefer to align with each other and form local order during migration. Although the underlying mechanisms remain unclear, utilizing their physical properties to achieve controllable cell-layer transport will be of fundamental importance. In this study, the ratchet effect is harnessed to control the collective motion of neural progenitor cells (NPCs) in vitro.
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