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Langmuir–Blodgett Trough
A Langmuir–Blodgett trough (LB trough) is a laboratory apparatus that is used to compress monolayers of molecules on the surface of a given subphase (usually water) and measures surface phenomena due to this compression. It can also be used to deposit single or multiple monolayers on a solid substrate. Description Overview The idea of a Langmuir–Blodgett (LB) film was first proven feasible in 1917 when Irving Langmuir (Langmuir, 1917) showed that single water-surface monolayers could be transferred to solid substrates. 18 years later, Katharine Blodgett made an important scientific advance when she discovered that several of these single monolayer films could be stacked on top of one another to make multilayer films (Blodgett 1935). Since then, LB films (and subsequently the troughs to make them) have been used for a wide variety of scientific experimentation, ranging from 2D crystallization of proteins to Brewster angle microscopy. The LB trough's general objective is to st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agnes Pockels
Agnes Luise Wilhelmine Pockels (14 February 1862 – 21 November 1935) was a German chemist whose research was fundamental in establishing the modern discipline known as surface science, which describes the properties of liquid and solid surfaces and interfaces. Pockels became interested in fundamental research in surface science through observations of soaps and soapy water in her own home while washing dishes. She devised a surface film balance technique to study the behavior of molecules such as soaps and surfactants at air-liquid interfaces. From these studies, Pockels defined the "Pockels Point" which is the minimum area that a single molecule can occupy in monomolecular films. Pockels was an autodidact. She was not a paid, professional scientist and had no institutional affiliation and so is an example of a citizen scientist. Early life and education Pockels was born in Venice, Italy, in 1862. At the time, Venice was under Austrian rule, and Pockels' father served ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Self-assembled Monolayer
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. SAMs are created by the chemisorption of "head groups" onto a substrate from either the vapor or liquid phase followed by a slow organization of "tail groups". Initially, at small molecular density on the surface, adsorbate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electron Tunneling
Quantum tunnelling, also known as tunneling ( US) is a quantum mechanical phenomenon whereby a wavefunction can propagate through a potential barrier. The transmission through the barrier can be finite and depends exponentially on the barrier height and barrier width. The wavefunction may disappear on one side and reappear on the other side. The wavefunction and its first derivative are continuous. In steady-state, the probability flux in the forward direction is spatially uniform. No particle or wave is lost. Tunneling occurs with barriers of thickness around 1–3 nm and smaller. Some authors also identify the mere penetration of the wavefunction into the barrier, without transmission on the other side as a tunneling effect. Quantum tunneling is not predicted by the laws of classical mechanics where surmounting a potential barrier requires sufficient kinetic energy. Quantum tunneling plays an essential role in physical phenomena such as nuclear fusion and alpha radioac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rheology
Rheology (; ) is the study of the flow of matter, primarily in a fluid (liquid or gas) state, but also as "soft solids" or solids under conditions in which they respond with Plasticity (physics), plastic flow rather than deforming Elasticity (physics), elastically in response to an applied force. Rheology is a branch of physics, and it is the science that deals with the Deformation (physics), deformation and flow of materials, both solids and liquids.W. R. Schowalter (1978) Mechanics of Non-Newtonian Fluids Pergamon The term ''wikt:rheology, rheology'' was coined by Eugene C. Bingham, a professor at Lafayette College, in 1920, from a suggestion by a colleague, Markus Reiner.The Deborah Number The term was inspired by the aphorism of Heraclitus (often mistakenly attributed to Simplicius of Cilicia, Simplicius), (, 'everything flows' [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optics
Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultraviolet, and infrared light. Because light is an electromagnetic wave, other forms of electromagnetic radiation such as X-rays, microwaves, and radio waves exhibit similar properties. Most optical phenomena can be accounted for by using the classical electromagnetic description of light. Complete electromagnetic descriptions of light are, however, often difficult to apply in practice. Practical optics is usually done using simplified models. The most common of these, geometric optics, treats light as a collection of rays that travel in straight lines and bend when they pass through or reflect from surfaces. Physical optics is a more comprehensive model of light, which includes wave effects such as diffraction and interference that c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amphiphiles
An amphiphile (from the Greek αμφις amphis, both, and φιλíα philia, love, friendship), or amphipath, is a chemical compound possessing both hydrophilic (''water-loving'', polar) and lipophilic (''fat-loving'') properties. Such a compound is called amphiphilic or amphipathic. Common amphiphilic substances are soaps, detergents, and lipoproteins. The phospholipid amphiphiles are the major structural component of cell membranes. Amphiphiles are the basis for a number of areas of research in chemistry and biochemistry, notably that of lipid polymorphism. Organic compounds containing hydrophilic groups at both ends of the molecule are called bolaamphiphilic. The micelles they form in the aggregate are prolate. Structure The lipophilic group is typically a large hydrocarbon moiety, such as a long chain of the form CH3(CH2)n, with n > 4. The hydrophilic group falls into one of the following categories: # charged groups #* anionic. Examples, with the lipophilic part of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hans Kuhn (chemist)
Hans Kuhn (5 December 1919 – 25 November 2012) was a Swiss chemist. He was professor emeritus for physical chemistry and former scientific director at the Max Planck Institute for Biophysical Chemistry (Karl Friedrich Bonhoeffer Institute) in Göttingen. Biography Curriculum Hans Kuhn was born in Bern, Switzerland. He studied chemistry at the ETH Zürich and worked for his doctorate at University of Basel under the guidance of Werner Kuhn (not related). He received his habilitation in 1946. From 1946 until 1947 he worked as a post doctoral fellow with Linus Pauling at Caltech in Pasadena and in 1950 with Niels Bohr in Copenhagen. In 1951, he became professor at the University of Basel. He was appointed in 1953 as professor and director of the Institute of Physical Chemistry of the Philipps University of Marburg where he stayed until 1970. Then he was at the Max Planck Institute for Biophysical Chemistry (Karl Friedrich Bonhoeffer Institute) in Göttingen as director of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Katherine Blodgett
Katharine Burr Blodgett (January 10, 1898 – October 12, 1979) was an American physicist and chemist known for her work on surface chemistry, in particular her invention of "invisible" or nonreflective glass while working at General Electric. She was the first woman to be awarded a PhD in physics from the University of Cambridge, in 1926. Early life Blodgett was born on January 10, 1898, in Schenectady, New York. She was the second child of Katharine Buchanan (Burr) and George Reddington Blodgett. Her father was a patent attorney at General Electric where he headed that department. He was shot and killed in his home by a burglar just before she was born. GE offered a $5,000 reward for the arrest and conviction of the killer, but the suspected killer hanged himself in his jail cell in Salem, New York. Her mother was financially secure after her husband's death, and she moved to New York City with Katharine and her son George Jr. shortly after Katharine's birth. In 1901, Katharin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neil Kensington Adam
Neil Kensington Adam (5 November 1891 – 19 July 1973) was a British chemist. Education Adam was born in Cambridge, the first of three children of James Adam (1860–1907), a Classics don, and his classicist wife Adela Marion (née Kensington) (1866–1944). His sister Barbara was a noted sociologist and criminologist, while his brother Captain Arthur Innes Adam was killed in France on 16 September 1916. His maternal uncle was Sir Alfred Kensington, a judge in the Chief Court of the Punjab. Adam was educated at Winchester College, and then studied chemistry at Trinity College, Cambridge, where he later became a fellow (1915–1923). He graduated BA in 1913, received his MA in 1919, and Sc.D in 1928. Career During the First World War, he served at the Royal Naval Air Service airship station at Kingsnorth, Kent, working on problems associated with rubber-proofing fabric for airships, and other chemical problems. Adam was Sorby Research Fellow at the University of Sheffie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
William Harkins
William Draper Harkins (December 28, 1873 – March 7, 1951) was an American physical chemist, noted for his contributions to surface chemistry and nuclear chemistry. Harkins researched the structure of the atomic nucleus and was the first to propose the principle of nuclear fusion, four years before Jean Baptiste Perrin published his theory in 1919-20. His findings enabled, among other things, the development of the H-bomb. As a visiting professor with Fritz Haber in 1909, he was introduced to the study of surface tension, and he began work on the theory of solutions and solubility during a visit to MIT in 1909-1910. Harkins was born in Titusville, Pennsylvania, and graduated with a PhD from Stanford University in 1907. He subsequently taught chemistry at the University of Montana from 1900 to 1912, and then spent the rest of his career at the University of Chicago. Harkins correctly predicted the existence of the neutron in 1920 (as a proton–electron complex) and was the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lord Rayleigh
John William Strutt, 3rd Baron Rayleigh, (; 12 November 1842 – 30 June 1919) was an English mathematician and physicist who made extensive contributions to science. He spent all of his academic career at the University of Cambridge. Among many honors, he received the 1904 Nobel Prize in Physics "for his investigations of the densities of the most important gases and for his discovery of argon in connection with these studies." He served as president of the Royal Society from 1905 to 1908 and as chancellor of the University of Cambridge from 1908 to 1919. Rayleigh provided the first theoretical treatment of the elastic scattering of light by particles much smaller than the light's wavelength, a phenomenon now known as "Rayleigh scattering", which notably explains why the sky is blue. He studied and described transverse surface waves in solids, now known as "Rayleigh waves". He contributed extensively to fluid dynamics, with concepts such as the Rayleigh number (a d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
