A5059849929- Spectroscopy and Quantum Chemical Studies
- Photochemistry and Electron Transfer Studies
- Molecular Junctions and Nanostructures
- Force Microscopy Techniques and Applications
- Surfactants and Colloidal Systems
- Spectroscopy and Laser Applications
- Electrochemical Analysis and Applications
- Glass properties and applications
- Nuclear materials and radiation effects
- Radiation Shielding Materials Analysis
- Mechanical and Optical Resonators
- Advanced Chemical Physics Studies
- Luminescence and Fluorescent Materials
- Chalcogenide Semiconductor Thin Films
- Advanced Fluorescence Microscopy Techniques
- Perovskite Materials and Applications
- Graphene research and applications
- Analytical Chemistry and Chromatography
- Near-Field Optical Microscopy
- Carbon and Quantum Dots Applications
- Gold and Silver Nanoparticles Synthesis and Applications
- Biosensors and Analytical Detection
- SARS-CoV-2 detection and testing
- Graphene and Nanomaterials Applications
- Lipid Membrane Structure and Behavior
Ohio University
2016-2025
Al-Azhar University – Gaza
2020
Imam Abdulrahman Bin Faisal University
2020
Oak Ridge National Laboratory
2012
University of Houston
2006-2011
Texas A&M University
2011
University of Wisconsin–Madison
2007
KTH Royal Institute of Technology
2007
Friction converts kinetic energy at sliding interfaces into lattice vibrations, but the detailed mechanisms of this process remain unresolved. Atomic force microscopy measurements reveal that changing mass terminating atoms on a surface, and thus their vibrational frequencies, affects nanoscale friction substantially. We compared hydrogen- deuterium-terminated single-crystal diamond silicon surfaces, in all cases hydrogenated surface exhibited higher friction. This result implies lower...
Nanoparticles (NPs) can be conjugated with diverse biomolecules and employed in biosensing to detect target analytes biological samples. This proven concept was primarily used during the COVID-19 pandemic gold-NP-based lateral flow assays (LFAs). Considering gold price its worldwide depletion, here we show that novel plasmonic NPs based on inexpensive metals, titanium nitride (TiN) copper covered a shell (Cu@Au), perform comparable or even better than nanoparticles. After conjugation, these...
The molecular orientation of trimethylamine N-oxide (TMAO), a powerful protein stabilizer, was explored at aqueous/hydrophobic interfaces using vibrational sum frequency spectroscopy (VSFS). systems studied included the octadecyltrichlorosilane (OTS)/water interface, which represents an aqueous solution in direct contact with hydrophobic medium. Surprisingly, measurements revealed that methyl groups TMAO pointed into phase and away from OTS. This may arise more hydrophilic nature attached to...
We explore a new glassy material for radiation shielding applications. Novel transparent and non-toxic Bi2O3–B2O3 glasses including different concentrations of CdO were prepared by the conventional melt quenching method. The samples characterized analyzed using various analytical tools (XRD, FTIR, Raman, DSC, UV-Vis-NIR). Ab initio molecular dynamics simulations carried out to create structural models materials, these compared our measurements. To best knowledge, this is first study compare...
Sum frequency generation imaging microscopy (SFGIM) is used to image the chemically distinct regions of a microcontact-printed monolayer surface. The contrast in images based on vibrational spectrum each component monolayer. Mixtures C16 thiols gold with CH3 and phenyl termination are imaged resolution approximately 10 microm. Microcontact printing produces films that different compared immersion procedure forming self-assembled monolayers. SFGIM technique able obtain at point surface...
Sum frequency generation imaging microscopy has been developed and implemented in different systems from self-assembled monolayer on metal surfaces to reaction of a surface upon exposure corrosive material (cyanide solution). It also helped the fundamental issues heterogeneity be understood by using mapping analysis that considers an acquired spectrum chosen region-of-interest independent its neighboring ROIs. The construction microscope utilized modified accommodate improvement spatial...
Sum frequency generation (SFG) imaging is used to monitor, in situ, the reaction of cyanide ions with gold surface. Spatial and chemical variations across surface are observed as a function time. The initial period resulted formation linearly bound gold, continuous exposure film solution led presence higher-coordinated gold−cyanide complexes. These species were identified by their specific position SFG vibrational spectrum (2105, 2140, 2170, 2225 cm−1). relative amounts these varied resolved...
The monoalkyl diamine surfactant, N-dodecylpropane-1,3-diamine (DPDA), is expected to exhibit a pH-dependent charge switchability. In response pH changes, the interfacial self-assembly of DPDA becomes an intermediary constituent that can potentially modify interactions and structural assembly both oil water phases. Hence, we hypothesize as change pH, will respond it by changing its alkyl tail conformation well adjacent phases at molecular level, consequently affecting emulsion formation...
Keratoprosthesis is an alternative treatment for visual impairment caused by corneal diseases. However, due to the recognized postoperative complications in available Kpros, there exigency explore potential skirt materials implants. This study aims investigate suitability of poly(2-methoxyethyl methacrylate-co-2-hydroxyethyl methacrylate) (15% MEMA: 85% HEMA), and poly(2-phenoxyethyl PhEMA: HEMA) copolymers as a implant material evaluating their ability adhere human keratocytes. The effect...
Sum frequency vibrational spectroscopy is utilized as an imaging technique to distinguish and compare the local response of carbon monoxide (CO) covered platinum (Pt) polycrystalline surface versus average investigated area. The Pt electrode was prepared using standard method exposed approximately 1 atm CO(g). SFG images spectra were obtained where contrast based on intrinsic nature each peak in CO spectrum. illustration chemical maps showed distribution across observed results by comparing...
An SFGVS study showed H-bonding interactions between the carbonyl groups of methacrylate liquid monomers and surface silanol amorphous quartz.
Understanding interfacial phenomena is important in processes like corrosion, catalysis, and electrochemical reactions. Specifically, corrosion inhibition, the assembly of adsorbed surfactants at metal–water interfaces well-packed, ordered layers desired. We provide direct evidence role alkyl tails formation interfaces. have employed surface-specific sum frequency generation (SFG) spectroscopy to probe situ adsorption self-assembly cationic surfactants, alkyldimethylbenzyl ammonium bromides...
Sum frequency generation imaging microscopy has been used to investigate a self-assembled monolayer of an alkanethiol (octadecanethiol, ODT) on mild steel surface. The images are analyze the orientation and distribution orientational angles as well defects in film. results show that, average, ODT forms ordered when compared same gold. However, image analysis suggests that tilt conformational is greater for surface ODT/Au.
The results of imaging μCP printed monolayers using sum frequency generation vibrational spectroscopy are presented, where the image contrast is based on orientation terminal methyl groups. regions contain thiols with 16 carbon atoms (even), and backfilled 17 (odd). In odd/even effect, group alternates its as number methylene changes from even to odd. On basis this result, SFG microscopy (SFGIM) used C16 C17 difference group. Furthermore, we compared patterns formed by C16/C17 n-alkanethiols...
Octadecanethiol (ODT) adsorbed onto zinc has been studied with sum frequency generation (SFG), imaging microscopy (SFG-IM), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), and electrical impedance (EIS) in order to investigate its corrosion protective ability conformational ordering. SFG shows that ODT forms an ordered adsorbate on both reduced oxidized within short times after immersion 1 mM ODT/ethanol solution. The protection, deduced by EIS, is also improved the After...
Monitoring and understanding monomer conformational changes as substituents are varied is an important step in investigating situ polymerization controlling the process well regulating functionality of polymer surfaces to provide efficient coatings. In this study, preliminary stage involves characterization interfacial structures methacrylate-based functional monomers their thin films at air–liquid interface using femtosecond sum frequency generation spectroscopy (FSFGS). By varying...
The geometry, arrangement, and orientation of a quaternary ammonium surfactant flanked by two methyl groups, benzyl head, an octyl tail were assessed at the air–water air-deuterium oxide (D2O) interfaces using sum frequency generation vibrational spectroscopy. Remarkably, symmetric asymmetric N–CH3 stretches (at ∼2979 ∼3045 cm–1, respectively, in SSP polarization combination) visible water but negligible deuterium oxide. We concluded that D2O addition triggers average reorientation dimethyl...
Sum frequency generation (SFG) microscopy was used to investigate the structure and orientation of multidentate alkanethiolate monolayers on gold surfaces. Adsorbate molecules in which one, two, or three sulfur atoms coordinated surface afforded self-assembled (SAMs) with controlled spacing between alkyl chains. SFG imaging determine visualize spatial variations across surface. Using imaging, average terminal methyl group is measured as well standard deviation. Further, presence film defects...
Functionalization of monomers is important for various applications polymers from electronics to surface coatings. Polymer chemists utilize methacrylate-based design with wider application features. In this work, ethyl are functionalized varying bulky substituents, methoxy (−OCH3), ethoxy (−OEt), isopropoxy (−OiPr), tert-butoxy (−OtBu), and phenoxy (−OPh), at the end position. These substituents selected understand steric consequences modification a bulkier group. This study allows...
This study employs femtosecond sum frequency generation (FS-SFG) spectroscopy to identify the functional groups at air–liquid interface of 2-methoxyethyl methacrylate (MEMA) monomer. Based on collected spectra, methoxy group (−OCH3), methylene (−CH2) from ethyl side chain MEMA, α-methyl (α-CH3), and alkene-methylene (═CH2) are present interface. Tilt angle was determined by calculating intensity ratio values fitting results, then ratios compared simulated SFG curves. The results derived...
Sensing in molecularly imprinted polymers (MIPs) requires specific interactions of the polymer and approaching template molecule. These are affected by morphology surface, affinity molecule to network, steric approach. In this particular study, a molecule, metronidazole, is studied with respect typically used methacrylic acid-based using combination bulk surface techniques. The resulting infrared (IR) spectra exhibited presence matrix as well their efficient removal after washing. Dipping...
Long-distance transmission of oil is usually performed in large-diameter steel pipelines, where water present therein may cause severe internal corrosion. An effective method mitigating such corrosion to inject organic inhibitors (CIs). Their surface adsorption, via heteroatom functionalities, can markedly enhance the resistance metals. In this study, three CI model compounds with different head groups but same alkyl tail length (-C14H29), specifically tetradecyltetrahydropyrimidinium...