- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Prototyping of Superhydrophobic Surfaces from Structure-Tunable Micropillar Arrays Using Visible Light Photocuring
摘要： A new approach is reported to fabricate micropillar arrays on transparent surfaces by employing the light-induced self-writing technique. A periodic array of microscale optical beams is transmitted through a thin film of photo-crosslinking acrylate resin. Each beam undergoes self-lensing associated to photopolymerization-induced changes in the refractive index of the medium, which counters the beam’s natural tendency to diverge over space. As a result, a microscale pillar grows along each beam’s propagation path. Concurrent, parallel self-writing of micropillars leads to the prototyping of micropillar-based arrays, with the capability to precisely vary the pillar diameter and inter-spacing. The arrays are spray coated with a thin layer of polytetrafluoroethylene (PTFE) nanoparticles to create large-area superhydrophobic surfaces with water contact angles greater than 150° and low contact angle hysteresis. High transparency is achieved over the entire range of micropillar arrays explored. The arrays are also mechanically durable and robust against abrasion. This is a scalable, straightforward approach toward structure-tunable micropillar arrays for functional surfaces and anti-wetting applications.
关键词： light-induced self-writing,re-entrant,micropillars,hydrophobicity,nanoparticles
更新于2025-10-24 16:36:04
-
Optical responses of BSA protein under re-entrant condensation in presence of trivalent ions
摘要： Fluorescence behavior of globular protein like BSA is studied under the re-entrant condensation in the presence of trivalent salts like YCl3 and LaCl3. BSA shows a re-entrant behaviour in solution where a specific turbid phase is formed between the two critical concentrations of the trivalent salts. Optical behaviours of proteins are explored by UV-Vis, photoluminescence and time resolved photoluminescence (TRPL) spectroscopy, whereas hydrodynamic size is obtained from the dynamic light scattering (DLS) technique. BSA shows maximum emission intensity at ≈ 338 nm for an excitation at 278 nm, however, the value of the peak intensity of emission gradually increases with the increase in salt concentration and becomes maximum at the turbid phase but for higher salt concentration as the re-dissolution takes place the emission intensity again decreases. TRPL study suggests that the decay time of BSA under re-entrant condensation is correlated with the salt concentration, whereas DLS study shows that the hydrodynamic size gradually increases up to a certain salt concentration where turbid phase is formed and then again decreases for higher salt concentrations. The variation of emission intensity of BSA nearly follows the modification of diffusion coefficient or hydrodynamic size and the phase transition behaviours.
关键词： UV-Vis spectroscopy,Bovine serum albumin,Tri-valent ions,Re-entrant condensation,Fluorescence spectroscopy
更新于2025-09-23 15:23:52
-
Study on Band-Gap Behaviors of 2D Hierarchical Re-Entrant Lattice Structures
摘要： An investigation of Poisson’s ratios and band gap behaviors of 2D hierarchical re-entrant lattice structures is conducted using finite element method (FEM). The structure with a hierarchy order n (n≥1) is constructed by replacing each outmost vertex of the re-entrant octagons of a hierarchical structure of hierarchy order n?1 with a smaller self-similar re-entrant octagon. The dispersion relation and transmission spectrum of the proposed hierarchical structures are analyzed based on the Bloch’s theorem. The effects of geometrical parameters, order of rotational symmetry and orientation angle of some types of re-entrant polygon cores on the lattice Poisson’s ratio and band gap structures are also investigated. Results show that the re-entrant structures with first order hierarchy exhibit a wider band gap and a stronger attenuation effect compared with structures without structural hierarchy. The first order 2D hierarchical re-entrant structure with a negative Poisson’s ratio of ?0.032 exhibits the widest band gap, 17.8% wider than that of the zeroth order 2D re-entrant structure. The order of rotational symmetry and the orientation angle of the re-entrant polygon cores of the lattice have a strong impact on the lattice Poisson’s ratio and band structures.
关键词： re-entrant,negative Poisson’s ratio,band gap,hierarchical structure,transmission spectrum
更新于2025-09-23 15:23:52
-
Experimental and computational studies on induced thermochromic effect and re-entrant smectic phase in linear double hydrogen-bonded binary liquid crystal mixtures
摘要： Design and synthesis of the hydrogen-bonded liquid crystalline (HBLC) mixtures are accomplished from diglycolic acid and 4-n-alkoxybenzoic acid (n = 9–12). Spectroscopic characterization such as UV–Vis, FT-IR, and DSC has supported the presence of molecular geometry of HBLC mixtures. Thermochromic effect is analyzed for the polarizing filter applications. Induced new phases (Smectic X and Smectic Cr) and their transitions are confirmed through DSC along with its corresponding optical textures using polarizing microscope. Furthermore, the induced re-entrant smectic ordering due to the lone pair to π* transition is reported using density functional theory (DFT) studies. Dipole moment studies (DFT) clearly give a strong evidence of the existence of nematic and smectic phases due to the monopole–dipole interaction in the present HBLC mixtures. Band gap of the present HBLCs is 5.175 eV, which is calculated by the HOMO–LUMO analysis and is validated using experimental observations. Liquid crystal parameters such as transition temperature, enthalpy values, stability factor and tilt angles are reported.
关键词： thermal stability,Nematic,DFT,re-entrant,thermochromic
更新于2025-09-23 15:22:29