A5102739743- Liquid Crystal Research Advancements
- Pickering emulsions and particle stabilization
- Material Dynamics and Properties
- Lipid Membrane Structure and Behavior
- Surfactants and Colloidal Systems
- Nanopore and Nanochannel Transport Studies
- Polysaccharides Composition and Applications
- Phase-change materials and chalcogenides
- Mesoporous Materials and Catalysis
- Electrohydrodynamics and Fluid Dynamics
- Chalcogenide Semiconductor Thin Films
- Innovative Microfluidic and Catalytic Techniques Innovation
- Synthesis and properties of polymers
- Proteins in Food Systems
- Gold and Silver Nanoparticles Synthesis and Applications
- Ionic liquids properties and applications
- Quantum, superfluid, helium dynamics
- Characterization and Applications of Magnetic Nanoparticles
- Quantum Dots Synthesis And Properties
- Membrane Separation Technologies
- Color Science and Applications
- Block Copolymer Self-Assembly
- Advanced Cellulose Research Studies
- Electrospun Nanofibers in Biomedical Applications
- RNA Interference and Gene Delivery
University of California, Santa Barbara
2020-2024
European Synchrotron Radiation Facility
2018-2023
European Science Foundation
2022
Kent State University
2014-2017
The hydrophobic collapse is a structural transition of grafted polymer chains in poor solvent. Although such seems an intrinsic event during clustering polymer-stabilized nanoparticles the liquid phase, it has not been resolved real time. In this work, we implemented microfluidic 3D-flow-focusing mixing reactor equipped with real-time analytics, small-angle X-ray scattering (SAXS), and UV-vis-NIR spectroscopy to study early stage cluster formation for polystyrene-stabilized gold...
A plasmon-based “stiffness nanoruler” paves the way for a cost-effective and high-throughput determination of mechanical properties synthetic biogenic nanometric vesicles at collective level.
Modern syntheses of colloidal nanocrystals yield extraordinarily narrow size distributions that are believed to result from a rapid "burst nucleation" (La Mer, JACS, 1950, 72(11), 4847-4854) followed by diffusion limited growth and distribution focusing (Reiss, J. Chem. Phys., 1951, 19, 482). Using combination in situ X-ray scattering, optical absorption, 13C nuclear magnetic resonance (NMR) spectroscopy, we monitor the kinetics PbS solute generation, nucleation, crystal three thiourea...
Successful implementation of the single-photon-counting Eiger 500k pixel array detector for sub-millisecond X-ray photon correlation spectroscopy (XPCS) measurements in ultra-small-angle scattering region is reported. The performance demonstrated by measuring dynamics dilute silica colloids aqueous solvents when operated at different counter depths, 4, 8 and 12 bit. In fastest mode involving 4 bit parallel readout, a stable frame rate 22 kHz obtained that enabled measurement...
The investigation of phononic collective excitations in soft matter systems at the molecular scale has always been challenging due to limitations experimental techniques resolving low-energy modes. Recent advances inelastic X-ray scattering (IXS) enabled study such with unprecedented spectral contrast meV excitation energies. In particular, it become possible shed light on motions materials whose morphology and phase behavior can easily be manipulated, as mesogenic systems. understanding...
Abstract Organic sulfur plays a crucial role in the biogeochemistry of aquatic sediments, especially low sulfate (< 500 μ M) environments like freshwater lakes and Earth's early oceans. To better understand organic cycling these systems, we followed sulfate‐poor 40 iron‐rich (30–80 sediments Lake Superior from source to sink. We identified microbial populations with shotgun metagenomic sequencing characterized geochemical species porewater solid phases. In anoxic found an active cycle...
This article presents the emergent dynamics of St\"ober and Janus colloids upon spinodal phase separation suspending medium investigated by dynamic X-ray scattering. Both manifest an enhanced dominated strong velocity fluctuations anomalous diffusion akin to superdiffusion.
A series of extended, symmetric viologen triflimides were synthesised by the metathesis reaction lithium triflimide with respective tosyalates in methanol. Their chemical structures characterised Fourier Transform Infrared, 1H and 13C Nuclear Magnetic Resonance spectroscopy elemental analysis. thermotropic liquid-crystalline (LC) properties examined a number experimental techniques including differential scanning calorimetry, thermogravimetric analysis, polarising optical microscopy variable...
Advances in modern interface- and material sciences often rely on the understanding of a system's structure-function relationship. Designing reproducible experiments that yield situ time-resolved structural information at fast time scales is therefore great interest, e.g., for better early stages self-assembly or other phase transitions. However, it can be challenging to accurately control experimental conditions, especially when samples are only available small amounts, prone agglomeration,...
A series of bis(4-alkoxyphenyl) viologen bis(triflimide) salts with alkoxy chains different lengths were synthesized by the metathesis reaction respective dichloride salts, which in turn prepared from Zincke salt corresponding 4-n-alkoxyanilines, lithium triflimide methanol. Their chemical structures characterized 1H and 13C nuclear magnetic resonance spectra elemental analysis. thermotropic liquid-crystalline (LC) properties examined differential scanning calorimetry, polarizing optical...
We have discovered the existence of polydisperse high internal-phase-ratio emulsions (HIPE) in which internal-phase droplets, present at 95% volume fraction, remain spherical and organise themselves according to Apollonian packing rules. These HIPEs are formed by emulsifying oil dropwise a surfactant-poor aqueous continuous phase. After stirring has ceased, their droplet size distributions begin evolve spontaneously continuously through coalescence towards well-defined power laws with...
The orientation behavior and the translational dynamics of spherical magnetic silica-nickel Janus colloids in an external field have been studied by small-angle X-ray scattering photon correlation spectroscopy at ultra small-angles. For weak applied fields low volume fractions, particle is dominated Brownian motion even though net moments individual particles are aligned direction as indicated anisotropy patterns. higher forces result more complex structural changes with nickel caps pointing...
Recent inelastic X-ray scattering (IXS) experiments on mesogens have revealed entirely new capabilities with regards to their nanoscale phonon-assisted heat management. Mesogens such as nematic liquid crystals (LCs) are appealing systems for study because structure and morphology can easily be tuned. We report Q-resolved ultra-high-resolution IXS, diffraction, THz time-domain spectroscopy combined large-scale all-atom molecular dynamics simulations the dynamic properties of 5CB LCs. For...
Recent studies of photoalignment liquid crystals (LCs) on chalcogenide surfaces have a rich variety mechanisms responsible for the these materials. Both surface-mediated and LC bulk-mediated were observed. We report investigation toward understanding origin photoalignment. The contributions light-induced optical surface morphological anisotropy studied. Light-induced in film was observed by polarization interferometry measured high-resolution x-ray reflectivity. data reveals lack strong...
We have used time-resolved small-angle X-ray scattering (SAXS) to study the adhesion of lipid vesicles in electrostatic strong-coupling regime induced by divalent ions. The bilayer structure and interbilayer distance dw between adhered was studied for different DOPC:DOPS mixtures varying surface charge density membrane, as well ions, such Ca2+, Sr2+, Zn2+. results are good agreement with strong coupling theory predicting state corresponding like-charge attraction based on ion-correlations....
A series of 4,4ʹ-dialkoxy-3,3ʹ-diaminobiphenyl compounds were synthesised by three-step procedure that involves alkylation, nitration and reduction reactions. Their chemical structures characterised FTIR, 1H 13C spectroscopy elemental analysis. thermotropic liquid–crystalline (LC) properties examined a number experimental techniques including differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), polarising optical microscopy (POM) variable temperature X-ray diffraction...
The orientation ordering and assembly behavior of silica-nickel Janus particles in a static external magnetic field were probed by ultra small-angle X-ray scattering (USAXS). Even weak applied field, the net moments individual aligned direction as indicated anisotropy recorded USAXS patterns. photon correlation spectroscopy (XPCS) measurements on these suspensions revealed that corresponding particle dynamics are primarily Brownian diffusion [Zinn, Sharpnack & Narayanan (2023). Soft Matter,...
The results of high-resolution x-ray reflectivity study nano-dimensionally thin arsenic trisulfide (As2S3) glass films reveal surface roughness anisotropy upon prolonged irradiation with polarized 436 nm blue light. correlates the photoinduced and LC photoalignment observed on these films. However, As2S3 film's thickness reduces drastically during experiments, ambient oxygen moisture penetrate film create a second altered layer top thicker As2S3. confirm viability for non-contact material...
We investigated the spectrum of density fluctuations a liquid crystal, CB7CB, in two different orientations by using high-resolution inelastic x-ray scattering. Our analysis, based on Bayesian principles, revealed that high-frequency collective excitations propagate through this mesoscale-ordered sample peculiar manner lies somewhere between those observed liquids and crystalline systems. Interestingly, when we probed longer length scales, more pronounced solid-like response emerged. This...
Organic sulfur plays a crucial role in the biogeochemistry of aquatic sediments, especially low sulfate (<500 μM) environments like freshwater lakes and Archean Ocean.To better understand organic cycling these systems, we followed Lake Superior sediments from source to sink.We identified microbial populations with shotgun metagenomic sequencing characterized geochemical species porewater solid phases.In anoxic found an active cycle fueled by oxidized at depth interface between dissolved...
Membrane-delimited compartments, as lipid vesicles, are ubiquitous in natural and synthetic systems. The mechanical properties of such vesicles crucial for several physical, chemical, biological processes. However, their accurate determination is still challenging requires sophisticated instruments data analysis. Here we report the first evidence that surface plasmon resonance (SPR) citrated gold nanoparticles (AuNPs) adsorbed on finely sensitive to vesicles’ properties. We leverage this...
<p><b>Membrane-delimited compartments, as lipid vesicles, are ubiquitous in natural and synthetic systems. The mechanical properties of such vesicles crucial for several physical, chemical, biological processes. However, their accurate determination is still challenging requires sophisticated instruments data analysis. Here we report the first evidence that surface plasmon resonance (SPR) citrated gold nanoparticles (AuNPs) adsorbed on finely sensitive to vesicles’ properties. We...