Surface science is the study of physical and chemical phenomena that occur at the interface of two phases,including solid–liquid interfaces,solid–gas interfaces,solid–vacuum interfaces,and liquid–gas interfaces. It includes the fields of surface chemistry and surface physics. Some related practical applications are classed as surface engineering. The science encompasses concepts such as heterogeneous catalysis,semiconductor device fabrication,fuel cells,self-assembled monolayers,and adhesives. Surface science is closely related to interface and colloid science. Interfacial chemistry and physics are common subjects for both. The methods are different. In addition,interface and colloid science studies macroscopic phenomena that occur in heterogeneous systems due to peculiarities of interfaces.
Raman spectroscopy is a spectroscopic technique typically used to determine vibrational modes of molecules,although rotational and other low-frequency modes of systems may also be observed. Raman spectroscopy is commonly used in chemistry to provide a structural fingerprint by which molecules can be identified.
Molecular engineering is an emerging field of study concerned with the design and testing of molecular properties,behavior and interactions in order to assemble better materials,systems,and processes for specific functions. This approach,in which observable properties of a macroscopic system are influenced by direct alteration of a molecular structure,falls into the broader category of “bottom-up”design.
Colloidal gold is a sol or colloidal suspension of nanoparticles of gold in a fluid,usually water. The colloid is coloured usually either wine red or blue-purple . Due to their optical,electronic,and molecular-recognition properties,gold nanoparticles are the subject of substantial research,with many potential or promised applications in a wide variety of areas,including electron microscopy,electronics,nanotechnology,materials science,and biomedicine.
Resonance Raman spectroscopy is a variant of Raman spectroscopy in which the incident photon energy is close in energy to an electronic transition of a compound or material under examination. This similarity in energy (resonance) leads to greatly increased intensity of the Raman scattering of certain vibrational modes,compared to ordinary Raman spectroscopy.
Self-assembled monolayers (SAM) of organic molecules are molecular assemblies formed spontaneously on surfaces by adsorption and are organized into more or less large ordered domains. In some cases molecules that form the monolayer do not interact strongly with the substrate. This is the case for instance of the two-dimensional supramolecular networks of e.g. perylenetetracarboxylic dianhydride (PTCDA) on gold or of e.g. porphyrins on highly oriented pyrolitic graphite (HOPG). In other cases the molecules possess a head group that has a strong affinity to the substrate and anchors the molecule to it. Such a SAM consisting of a head group,tail and functional end group is depicted in Figure 1. Common head groups include thiols,silanes,phosphonates,etc.
Surface-enhanced Raman spectroscopy or surface-enhanced Raman scattering (SERS) is a surface-sensitive technique that enhances Raman scattering by molecules adsorbed on rough metal surfaces or by nanostructures such as plasmonic-magnetic silica nanotubes. The enhancement factor can be as much as 1010 to 1011,which means the technique may detect single molecules.
A nanoprobe is an optical device developed by tapering an optical fiber to a tip measuring 100 nm = 1000 angstroms wide.
The technique of vibrational analysis with scanning probe microscopy allows probing vibrational properties of materials at the submicrometer scale,and even of individual molecules. This is accomplished by integrating scanning probe microscopy (SPM) and vibrational spectroscopy. This combination allows for much higher spatial resolution than can be achieved with conventional Raman/FTIR instrumentation. The technique is also nondestructive,requires non-extensive sample preparation,and provides more contrast such as intensity contrast,polarization contrast and wavelength contrast,as well as providing specific chemical information and topography images simultaneously.
A localized surface plasmon (LSP) is the result of the confinement of a surface plasmon in a nanoparticle of size comparable to or smaller than the wavelength of light used to excite the plasmon. When a small spherical metallic nanoparticle is irradiated by light,the oscillating electric field causes the conduction electrons to oscillate coherently. When the electron cloud is displaced relative to its original position,a restoring force arises from Coulombic attraction between electrons and nuclei. This force causes the electron cloud to oscillate. The oscillation frequency is determined by the density of electrons,the effective electron mass,and the size and shape of the charge distribution. The LSP has two important effects:electric fields near the particle's surface are greatly enhanced and the particle's optical absorption has a maximum at the plasmon resonant frequency. Surface plasmon resonance can also be tuned based on the shape of the nanoparticle. The plasmon frequency can be related to the metal dielectric constant. The enhancement falls off quickly with distance from the surface and,for noble metal nanoparticles,the resonance occurs at visible wavelengths. Localized surface plasmon resonance creates brilliant colors in metal colloidal solutions.
Tip-enhanced Raman spectroscopy (TERS) is a variant of surface-enhanced Raman spectroscopy (SERS) that combines scanning probe microscopy with Raman spectroscopy. High spatial resolution chemical imaging is possible via TERS,with routine demonstrations of nanometer spatial resolution under ambient laboratory conditions,or better at ultralow temperatures and high pressure.
Droplet-based microfluidics manipulate discrete volumes of fluids in immiscible phases with low Reynolds number and laminar flow regimes. Interest in droplet-based microfluidics systems has been growing substantially in past decades. Microdroplets offer the feasibility of handling miniature volumes of fluids conveniently,provide better mixing,encapsulation,sorting,sensing and are suitable for high throughput experiments. Two immiscible phases used for the droplet based systems are referred to as the continuous phase and dispersed phase.
Shuming Nie is a Chinese-American chemist. He is the Grainger Distinguished Chair in Bioengineering at the University of Illinois at Urbana-Champaign. He was the Wallace H. Coulter Distinguished Faculty Chair in Biomedical Engineering at Emory University. In 2007,Nie was elected as a fellow of the American Institute for Medical and Biological Engineering (AIMBE). In 2012,Nie was elected as a fellow of the American Association for the Advancement of Science (AAAS).
Christy Lynn Haynes is a chemist at the University of Minnesota. She works at the interface of analytical,biological,and nanomaterials chemistry.
Karen Jane Faulds is a Scottish academic and Professor of Analytical Chemistry at the University of Strathclyde. She develops surface-enhanced Raman spectroscopy (SERS) for bioanalysis,and has won several awards for her research,including the Coblentz Society Craver Award.
Robin L. Garrell is an American chemist,academic and former president of The Graduate Center,CUNY. Until 2020,Garrell served as vice provost for graduate education and dean of graduate division at University of California,Los Angeles (UCLA). Prior to this role,Garrell was assistant professor at the University of Pittsburgh from 1984 to 1991,then joined the faculty in the department of chemistry and biochemistry at UCLA,where she became full professor and held a joint appointment in bioengineering. Garrell assumed her current position at The Graduate Center on August 1,2020. </ref>On August 28,2023 she announced that she would be stepping down as president of the CUNY Graduate Center effective September 29,2023.
Raman spectroelectrochemistry (Raman-SEC) is a technique that studies the inelastic scattering or Raman scattering of monochromatic light related to chemical compounds involved in an electrode process. This technique provides information about vibrational energy transitions of molecules,using a monochromatic light source,usually from a laser that belongs to the UV,Vis or NIR region. Raman spectroelectrochemistry provides specific information about structural changes,composition and orientation of the molecules on the electrode surface involved in an electrochemical reaction,being the Raman spectra registered a real fingerprint of the compounds.
Alexis Tarassov Bell is an American chemical engineer. He is currently the Dow professor of Sustainable Chemistry in the Department of Chemical and Biomolecular Engineering in UC Berkeley's college of chemistry. He is also the Faculty Senior Scientist at Lawrence Berkeley National Laboratory. He is known for his work with heterogenous catalysts and characterizing the mechanisms of these reactions on a quantum level.
Janina Kneipp is a German scientist who is Professor of Physical Chemistry Humboldt University of Berlin. Her research considers surface enhanced Raman scattering and plasmonic enhancement in multi-modal micro spectroscopy.
Richard P. Van Duyne (1945–2019) was an American chemist and professor of chemistry at Northwestern University. He was known for his development of surface-enhanced Raman scattering (SERS) and nanoplasmonics initially for analytical and physical chemistry,but the high sensitivity of these methods resulted in numerous applications in chemistry,material science,physics,and medicine. He definitively demonstrated the single molecule sensitivity of SERS.
