Article
Materials Science, Multidisciplinary
Mahyar Mazloumi, Eoin Dawson, Ribal Georges Sabat
Summary: Bessel laser beams generated by an axicon lens were used for the fabrication of hierarchical concentric surface patterns onto azobenzene molecular glass thin films. The resulting structures were characterized in details by atomic force and scanning electron microscopy, as well as surface profilometry, as the fabrication parameters were modified during the laser inscription process. It was found that the hierarchical concentric surface patterns on the azobenzene film reached overall heights that are surprisingly 5 times larger than the original film thickness. The presented axicon interference lithography technique was also used to fabricate novel metasurfaces on azobenzene thin films.
Article
Chemistry, Multidisciplinary
Xiaoyan Yang, Haibao Jin, Xinfeng Tao, Yuan Yao, Yufeng Xie, Shaoliang Lin
Summary: A simple strategy for the preparation of photo-responsive azobenzene-containing inverse opal (AzoIO) films with adjustable structural colors in wide visible wavelength is reported. The study demonstrates the potential for developing promising optical anti-counterfeiting materials.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Wen-Cong Xu, Chengwei Liu, Shuofeng Liang, Dachuan Zhang, Yazhi Liu, Si Wu
Summary: The study introduces a novel orthogonal photopatterning technique for fabricating noninterfering dual-mode patterns on an azopolymer P1, which exhibits photoinduced reversible solid-to-liquid transitions and good stretchability. The photonic structures and chromatic polarization in the dual-mode patterns are noninterfering, and the patterns are rewritable via various processing methods.
ADVANCED MATERIALS
(2022)
Article
Optics
Mingyuan Ren, Huajun Zhang, Wenkai Yao, Ning Zhou, Jianrui Gong, Yu Zhang
Summary: This paper investigates the spatial intensity correlations of transmitted speckle patterns generated by large particles. A semi-empirical expression of spatial intensity correlation function is derived based on the Bethe-Salpeter equation. Experimental results confirm the feasibility of the theoretical model, and the variation of spatial intensity correlation function with particle size and concentration is analyzed. The research findings have potential applications in coherent imaging through random and disordered media.
Article
Optics
Abhijit Roy
Summary: A technique based on intensity basis addition of two speckle patterns with polarization diversity is proposed. It is shown that by tuning the polarization diversity, a complete control over the spatial coherence of the superposed speckle pattern can be achieved. The modulation of spatial coherence depends not only on the polarization vectors of the constituent speckle patterns, but also on the sum of the polarization orientations, especially if the original field is not completely depolarized. The potential application of this work is in biomedical imaging, where speckle noise reduction is important.
OPTICS AND LASERS IN ENGINEERING
(2023)
Article
Polymer Science
Dexin Kong, Wenguang Wei, Xiujuan Zhi, Bin Du, Xiangning Chen
Summary: Composite films PVA-CS-Cur(x) (x = 0, 0.01, 0.06 and 0.12%) were obtained via vacuum-drying at 80 degrees C, improving the thermal stability, water-resistance, and mechanical property of films. The oxygen permeability of PVA-CS-Cur(x) showed dependence on test temperature and curcumin concentration. The films demonstrated excellent antibacterial capability and potential application in food decontamination.
JOURNAL OF APPLIED POLYMER SCIENCE
(2023)
Article
Optics
Swathi Erekath, Sreeram K. Kalpathy
Summary: Ordered patterns with nanoscale features and resolutions ranging from 5-75 μm are produced from thin films of azo-polyurea (azo-PU) using photoinduced dewetting. The reversible isomerization between cis-trans states is exploited to switch between pillar-like and hole-like morphologies. Marangoni flow is found to be the dominant mechanism controlling the morphological evolution of the patterns.
OPTICS AND LASER TECHNOLOGY
(2021)
Article
Materials Science, Multidisciplinary
Alexandre Silva, Ignasi Fina, Florencio Sanchez, Jose P. B. Silva, Luis Marques, Veniero Lenzi
Summary: We investigated the influence of La content on the structural and ferroelectric properties of epitaxial HfO2 films. It was found that 2-5 at. % La-doped HfO2 films exhibit optimum remanent polarization and reduced coercive field. Density functional theory calculations supported the experimental results and revealed that the polarization switching in epitaxial La:HfO2 films can be understood based on the synergetic contribution of a non-ferroelectric monoclinic phase and La doping itself.
MATERIALS TODAY PHYSICS
(2023)
Article
Chemistry, Physical
Fan Yang, Shengcun Ma, Chia Miang Khor, Yiming Su, Zahra Barani, Zhenpeng Xu, Arthur Boyko, Arpita Iddya, Naama Segev-Mark, Xiaoyu (Rayne) Zheng, Fariborz Kargar, Alexander A. Balandin, Guy Ramon, Igor De Rosa, Eric Hoek, David Jassby
Summary: To protect circuits from electromagnetic interference, lightweight, thin, and robust electromagnetic shielding materials with high electrical conductivity are required for advanced modern electronics and telecommunication technologies. Carbon nanotubes (CNT) have excellent mechanical strength, high electrical conductivity, and light weight, making them ideal candidates for electromagnetic shielding materials. A facile CNT film fabrication method was proposed in this study to enhance the conductivity of CNT films by densifying the material through collapsing the separation between neighboring CNTs.
Article
Engineering, Environmental
Liyuan Han, Kezhi Li, Huimin Liu, Yameng Jiao, Xuemin Yin, Hejun Li, Qiang Song, Lehua Qi
Summary: Facing the challenges of heat dissipation and electromagnetic interference in electronics, carbon modified polymer-based composites with significant EMI shielding and thermal management performance were developed. A carbon heterogeneous stacking strategy was proposed to construct all carbon aerogels for modifying epoxy resin, resulting in a hybrid 3D structure of reduced graphene oxide-carbon nanotube-vertical edge-rich graphene with covalent bonding. The designed microstructure of the rGO-CNT-VG skeleton provided plenty of seamlessly bonded heterogeneous interfaces, leading to enhanced electromagnetic microwave attenuation and conversion, and ideal EMI shielding performance.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Computer Science, Software Engineering
Shlomi Steinberg, Pradeep Sen, Ling-Qi Yan
Summary: This paper presents a novel framework for physical light transport, which accurately represents the wave nature of light and achieves precise rendering of wave-interference and diffraction effects in complex scenes. By introducing new rendering primitives and a wave BSDF, along with an approach for importance sampling, the efficiency of rendering is improved, approaching that of classical rendering methods.
ACM TRANSACTIONS ON GRAPHICS
(2022)
Article
Multidisciplinary Sciences
Alexey Porfirev, Svetlana Khonina, Nikolay Ivliev, Alexei Meshalkin, Elena Achimova, Andrew Forbes
Summary: Azobenzene-containing polymers are efficient and versatile photonic materials used for the fabrication of linear diffraction gratings and spectral filters. This study proposes a method using carbazole-containing azopolymer thin films to visualize the longitudinal component of the incident laser beam, and successfully demonstrates detection and fabrication of microstructures with structured light.
SCIENTIFIC REPORTS
(2022)
Article
Engineering, Biomedical
C. C. Wachesk, S. H. Seabra, T. A. T. Dos Santos, V. J. Trava-Airoldi, A. O. Lobo, F. R. Marciano
Summary: The study investigated the in vivo inflammatory process of DLC coatings with incorporated TiO2 nanoparticles for the first time, revealing their biocompatibility and enhanced wound healing activity. The presence of TiO2 nanoparticles reduced inflammatory reactions, increasing DLC biocompatibility.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN MEDICINE
(2021)
Article
Materials Science, Ceramics
Preeti Chaudhary, Akansha Agrwal, Dhirendra K. Sharma, Vipin Kumar
Summary: Pure and Yb-doped ZnO gels were prepared via sol-gel process, and their structure and optical properties were altered by doping. The electrical resistivity increased with increasing Yb-doping concentration.
JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
(2022)
Article
Materials Science, Ceramics
Jian Cheng Bi, Hyesun Yun, Minsong Cho, Min-Gi Kwak, Byeong-Kwon Ju, Youngmin Kim
Summary: Graphene has high thermal conductivity but is prone to tearing, limiting its use as a thermal interface material in flexible electronics. This study fabricated graphene composite films by infiltrating thermoplastic polymers into graphene patterns, achieving high thermal conductivity and preventing tearing.
CERAMICS INTERNATIONAL
(2022)
Article
Materials Science, Textiles
Huipu Gao, Darya Asheghali, Nataraja Sekhar Yadavalli, Minh Thien Pham, Tho Duc Nguyen, Sergiy Minko, Suraj Sharma
JOURNAL OF THE TEXTILE INSTITUTE
(2020)
Article
Physics, Applied
Joachim Jelken, Carsten Henkel, Svetlana Santer
APPLIED PHYSICS LETTERS
(2020)
Article
Biochemistry & Molecular Biology
Anjali Sharma, Marek Bekir, Nino Lomadze, Svetlana Santer
Summary: Ionic complexation of azobenzene-containing surfactants with oppositely charged soft objects enables photo-responsive changes in size, shape, and surface energy. The photo-isomerization of the cationic surfactant is slower in polymer complexes compared to being dissolved in aqueous solution, likely due to the formation of surfactant aggregates near polyelectrolyte chains, inhibiting the kinetics.
Article
Polymer Science
Maria Simonova, Ivan Ivanov, Tamara Meleshko, Alexey Kopyshev, Svetlana Santer, Alexander Yakimansky, Alexander Filippov
Article
Chemistry, Multidisciplinary
Joachim Jelken, Se-Hyeong Jung, Nino Lomadze, Yulia D. Gordievskaya, Elena Yu Kramarenko, Andrij Pich, Svetlana Santer
Summary: This study suggests a new approach of using light-triggered reversible switching to change the volume of microgels, demonstrating the ability to reversibly change the microgel radius by a factor of 3 using UV or green light irradiation at a fixed temperature. The possibility of quickly adjusting the swelling behavior of microgels through external means may impact and redefine the application of microgels in various fields.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Martin Reifarth, Marek Bekir, Alain M. Bapolisi, Evgenii Titov, Fabian Nusshardt, Julius Nowaczyk, Dmitry Grigoriev, Anjali Sharma, Peter Saalfrank, Svetlana Santer, Matthias Hartlieb, Alexander Boeker
Summary: A cationic surfactant with a spiropyrane unit was prepared, demonstrating adjustable surface-active characteristics with dual responsiveness. The reversible conversion of the spiropyrane unit to a zwitterionic merocyanine was controlled by adjusting pH value and light, resulting in pH-dependent photoactivity. The underlying switching processes were investigated and a thermodynamic explanation was provided. The complex stimuli-responsive behavior enables remote-control of colloidal systems and can be applied in pH-dependent manipulation of oil-in-water emulsions.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Materials Science, Multidisciplinary
Sarah Loebner, Bharti Yadav, Nino Lomadze, Nina Tverdokhleb, Hendrik Donner, Marina Saphiannikova, Svetlana Santer
Summary: This study reveals the relationship between photoinduced deformation of azobenzene containing polymers and the direction of optomechanical stresses generated during irradiation with interference patterns. Experimentally observed shapes are accurately reproduced with modeling using visco-plastic properties in finite element software. The orientation approach can predict local variations of light-induced stress in different interference patterns, providing a self-sufficient and convincing mechanism for describing photoinduced deformation in azopolymer films.
MACROMOLECULAR MATERIALS AND ENGINEERING
(2022)
Article
Instruments & Instrumentation
Md Mazbah Uddin, Brianna Blevins, Nataraja Sekhar Yadavalli, Minh Thien Pham, Tho Duc Nguyen, Sergiy Minko, Suraj Sharma
Summary: The concept of nanogenerators based on textiles is introduced for developing smart textiles and integrating wearable electronics. Two simple methods for constructing nanogenerators on fabrics are presented, showing their potential in powering low power consuming wearable electronics.
SMART MATERIALS AND STRUCTURES
(2022)
Article
Chemistry, Multidisciplinary
Anjali Sharma, Marek Bekir, Nino Lomadze, Se-Hyeong Jung, Andrij Pich, Svetlana Santer
Summary: This study demonstrates that microgels trapped at a solid wall can generate liquid flow and transport over long distances. The flow is induced by the response of microgels to irradiation, causing changes in their volume and creating concentration and osmotic pressure gradients that drive the flow. The direction and strength of the flow depend on the irradiation parameters and the amount of solute absorbed by the microgels.
Article
Polymer Science
Nina Tverdokhleb, Sarah Loebner, Bharti Yadav, Svetlana Santer, Marina Saphiannikova
Summary: This article explores two intriguing issues regarding the inscription of surface relief gratings within azopolymer thin films under different interference patterns. By utilizing the orientation approach and viscoplastic modeling in combination with experimental results, the study reveals that the initial orientation state of polymer backbones is responsible for the contradictory experimental reports on the efficiency of the SS interference pattern. Additionally, the study shows that the faster growth of gratings inscribed by the RL interference pattern is promoted by a weak photosoftening effect. Overall, the modeled results agree well with the order of relative growth efficiency: RL-PP-SS.
Article
Chemistry, Multidisciplinary
Marek Bekir, Marcel Sperling, Daniela Vasquez Munoz, Cevin Braksch, Alexander Boeker, Nino Lomadze, Mihail N. Popescu, Svetlana Santer
Summary: Separation of particles by size, morphology, or material identity is important in filtration or bioanalytics. However, the separation of particles solely based on surface properties or bulk/surface morphology remains challenging. This study proposes a combination of pressure-driven microfluidic flow and local self-phoresis/osmosis induced by a photoactive azobenzene-surfactant solution. The separated colloidal components experience different regions of the ambient microfluidic shear flow, allowing for a simple, versatile method of particle chromatography.
ADVANCED MATERIALS
(2023)
Article
Multidisciplinary Sciences
Dina V. Shmeliova, Sergey V. Pasechnik, Semen S. Kharlamov, Alexander V. Dubtsov, Alexandre V. Zakharov, Sarah Loebner, Svetlana Santer
Summary: This paper presents the first experimental results on capillary shear flows of a nematic liquid crystal 5CB (4-cyano-4'-pentylbiphenyl) induced by the interaction with photo-profiled polymer surfaces. The surface relief was optically created by irradiating an azobenzene-containing polymer film, resulting in a regular submicron profile with well-defined characteristics. The direction of surface orientation and anchoring strength of the liquid crystal were determined using polarizing microscopy and dynamic light scattering techniques. Different types of shear flows were investigated, showing strong anisotropy in the dynamics of film and contact line motion.
Article
Engineering, Chemical
Marek Bekir, Sarah Loebner, Alexej Kopyshev, Nino Lomadze, Svetlana Santer
Summary: We present a light-triggered process for remotely controlling repulsive interactions between microparticles with a polyelectrolyte (PE) brush coating. The process involves reversible photo-isomerization of a photosensitive azobenzene containing surfactant, which alters the hydrophilicity of the surfactant and generates a concentration gradient of cis isomers near a solid surface. This concentration gradient induces a local lateral diffusioosmotic flow, resulting in long-range repulsive interactions between the particles.
Article
Chemistry, Physical
Richard A. Campbell, Talmira Kairaliyeva, Svetlana Santer, Emanuel Schneck, Reinhard Miller
Summary: In this study, the interfacial composition during and after the interactions of a saturated atmosphere of oil vapor with soluble surfactant solutions at a planar water/air interface was directly resolved. The experiments revealed the balance between cooperativity and competition of the components at the interface.
COLLOIDS AND INTERFACES
(2022)
Proceedings Paper
Materials Science, Multidisciplinary
Joachim Jelken, Marius Brinkjans, Carsten Henkel, Svetlana Santer
PHOTOSENSITIVE MATERIALS AND THEIR APPLICATIONS
(2020)
