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Dendronized Polymer
In polymer chemistry and materials science, dendronized polymers (American and British English spelling differences, British English: dendronised polymers; ) are linear polymers to every repeat unit of which dendrons are attached. Dendrons are regularly-Branching (polymer chemistry), branched, tree-like fragments and for larger ones the polymer backbone is wrapped to give sausage-like, cylindrical molecular objects. Figure 1 shows a cartoon representation with the backbone in red and the dendrons like cake slices in green. It also provides a concrete chemical structure showing a polymethylmethacrylate (PMMA) backbone, the methyl group () of which is replaced by a dendron of the third generation (three consecutive branching points). Figure 1. Cartoon representation (left) and a concrete example of a third generation dendronized polymer (right). The peripheral amine groups are modified by a substituent X which often is a protection group. Upon deprotection and modification substant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymer Chemistry
Polymer chemistry is a sub-discipline of chemistry that focuses on the structures, chemical synthesis, and chemical and physical properties of polymers and macromolecules. The principles and methods used within polymer chemistry are also applicable through a wide range of other chemistry sub-disciplines like organic chemistry, analytical chemistry, and physical chemistry. Many materials have polymeric structures, from fully inorganic metals and ceramics to DNA and other biological molecules. However, polymer chemistry is typically related to synthetic and organic compositions. Synthetic polymers are ubiquitous in commercial materials and products in everyday use, such as plastics, and rubbers, and are major components of composite materials. Polymer chemistry can also be included in the broader fields of polymer science or even nanotechnology, both of which can be described as encompassing polymer physics and polymer engineering.Hans-Heinrich Moretto, Manfred Schulz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyacetylene
Polyacetylene (IUPAC name: polyethyne) usually refers to an organic polymer with the repeating unit . The name refers to its conceptual construction from polymerization of acetylene to give a chain with repeating olefin groups. This compound is conceptually important, as the discovery of polyacetylene and its high Ionic conductivity (solid state), conductivity upon doping (semiconductor), doping helped to launch the field of organic conductive polymers. The high electrical conductivity discovered by Hideki Shirakawa, Alan Heeger, and Alan MacDiarmid for this polymer led to intense interest in the use of organic compounds in microelectronics (organic semiconductors). This discovery was recognized by the Nobel Prize in Chemistry in 2000. Early work in the field of polyacetylene research was aimed at using doped polymers as easily processable and lightweight "plastic metals". Despite the promise of this polymer in the field of conductive polymers, many of its properties such as insta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macromonomer
In polymer chemistry, a macromonomer (or macromer) is a macromolecule with one end-group that enables it to act as a reactive monomer and undergo further polymerization. Macromonomers will contribute a single repeat unit to a chain of the completed macromolecule. Several macromonomers have been successfully synthesized utilizing various methods such as controlled radical polymerization (CRP) and copper-catalyzed "click" coupling. Due to the larger size of macromonomers (as opposed to the size of regular monomer A monomer ( ; ''mono-'', "one" + '' -mer'', "part") is a molecule that can react together with other monomer molecules to form a larger polymer chain or two- or three-dimensional network in a process called polymerization. Classification Chemis ...s), synthetic challenges are brought about, giving reason for the analysis of polymerization mechanisms. Recent studies have shown that macromonomer polymerization kinetics and mechanisms can be significantly affected by the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atomic Force Microscopy
Atomic force microscopy (AFM) or scanning force microscopy (SFM) is a very-high-resolution type of scanning probe microscopy (SPM), with demonstrated resolution on the order of fractions of a nanometer, more than 1000 times better than the optical diffraction limit. Overview Atomic force microscopy (AFM) gathers information by "feeling" or "touching" the surface with a mechanical probe. Piezoelectric elements that facilitate tiny but accurate and precise movements on (electronic) command enable precise scanning. Despite the name, the Atomic Force Microscope does not use the nuclear force. Abilities and spatial resolution The AFM has three major abilities: force measurement, topographic imaging, and manipulation. In force measurement, AFMs can be used to measure the forces between the probe and the sample as a function of their mutual separation. This can be applied to perform force spectroscopy, to measure the mechanical properties of the sample, such as the sample's Youn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanoparticle
A nanoparticle or ultrafine particle is a particle of matter 1 to 100 nanometres (nm) in diameter. The term is sometimes used for larger particles, up to 500 nm, or fibers and tubes that are less than 100 nm in only two directions. At the lowest range, metal particles smaller than 1 nm are usually called atom clusters instead. Nanoparticles are distinguished from microparticles (1-1000 μm), "fine particles" (sized between 100 and 2500 nm), and "coarse particles" (ranging from 2500 to 10,000 nm), because their smaller size drives very different physical or chemical properties, like colloidal properties and ultrafast optical effects or electric properties. Being more subject to the Brownian motion, they usually do not sediment, like colloid, colloidal particles that conversely are usually understood to range from 1 to 1000 nm. Being much smaller than the wavelengths of visible light (400-700 nm), nanoparticles cannot be seen with ordinary ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angewandte Chemie
''Angewandte Chemie'' (, meaning "Applied Chemistry") is a weekly peer-reviewed scientific journal that is published by Wiley-VCH on behalf of the German Chemical Society (Gesellschaft Deutscher Chemiker). Publishing formats include feature-length reviews, short highlights, research communications, minireviews, essays, book reviews, meeting reviews, correspondences, corrections, and obituaries. This journal contains review articles covering all aspects of chemistry. According to the ''Journal Citation Reports'', the journal had a 2023 impact factor of 16.1. Editions The journal appears in two editions with separate volume and page numbering: a German edition, ''Angewandte Chemie'', and a fully English-language edition, ''Angewandte Chemie International Edition''. The editions are identical in content with the exception of occasional reviews of German-language books or German translations of IUPAC recommendations. Publication history In 1887, Ferdinand Fischer established the '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molar Masses
In chemistry, the molar mass () (sometimes called molecular weight or formula weight, but see Molar mass#Related quantities, related quantities for usage) of a chemical substance (Chemical element, element or chemical compound, compound) is defined as the ratio between the mass () and the amount of substance (, measured in mole (unit), moles) of any sample of the substance: . The molar mass is a bulk, not molecular, physical property, property of a substance. The molar mass is a Weighted arithmetic mean, ''weighted'' ''average'' of many instances of the element or compound, which often vary in mass due to the presence of isotopes. Most commonly, the molar mass is computed from the standard atomic weights and is thus a terrestrial average and a function of the relative Abundance of the chemical elements, abundance of the isotopes of the constituent atoms on Earth. The molecular mass (for molecular compounds) and formula mass (for non-molecular compounds, such as ionic salts) are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Poly(ethylene Imine)
Polyethylenimine (PEI) or polyaziridine is a polymer with repeating units composed of the amine group and two carbon Aliphatic_compound, aliphatic ''CHCH'' spacers. Linear polyethyleneimines contain all Amines#Classification_of_amines, secondary amines, in contrast to branched PEIs which contain primary, secondary and tertiary amino groups. Totally branched, dendrimeric forms were also reported. PEI is produced on an industrial scale and finds many applications usually derived from its polyelectrolyte, polycationic character. Properties The linear PEI is a semi-crystalline solid at room temperature while branched PEI is a fully amorphous polymer existing as a liquid at all molecular weights. Linear polyethyleneimine is soluble in hot water, at low pH, in methanol, ethanol, or chloroform. It is insoluble in cold water, benzene, Diethyl ether, ethyl ether, and acetone. Linear polyethylenimine has a melting point of around 67 °C. Both linear and branched polyethylneimine c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polysiloxane
In organosilicon and polymer chemistry, a silicone or polysiloxane is a polymer composed of repeating units of siloxane (, where R = organic group). They are typically colorless oils or rubber-like substances. Silicones are used in sealants, adhesives, lubricants, medicine, cooking utensils, thermal insulation, and electrical insulation. Some common forms include silicone oil, grease, rubber, resin, and caulk. Silicone is often confused with one of its constituent elements, silicon, but they are distinct substances. Silicon is a chemical element, a hard dark-grey semiconducting metalloid, which in its crystalline form is used to make integrated circuits ("electronic chips") and solar cells. Silicones are compounds that contain silicon, carbon, hydrogen, oxygen, and perhaps other kinds of atoms as well, and have many very different physical and chemical properties. History F. S. Kipping coined the word ''silicone'' in 1901 to describe the formula of polydiphenylsiloxa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Poly(phenylene Acetylene)
Poly, from the Greek πολύς meaning "many" or "much", may refer to: Businesses * China Poly Group Corporation, a Chinese business group, and its subsidiaries: ** Poly Property, a Hong Kong incorporated Chinese property developer ** Poly Real Estate, a Chinese real estate developer ** Poly Technologies, a defense manufacturing company * Poly (company), formerly Polycom, an American communications technology company People * Poly (footballer) (1906-1986), full name Policarpo Ribeiro de Oliveira, Brazilian footballer * Natasha Poly (born 1985), stage name of Russian supermodel Natalya Sergeyevna Polevshchikova * Poly Styrene (1957–2011), stage name of British musician Marianne Joan Elliott-Said Polytechnic * Hong Kong Polytechnic University, locally known as Poly * Polytechnic Heights, Fort Worth, Texas, neighborhood locally known as Poly * Polytechnic Institute of NYU (now New York University Tandon School of Engineering), locally known as Poly * ''The Rensselaer Pol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Poly(phenylene Vinylene)
Poly(''p''-phenylene vinylene) (PPV, or polyphenylene vinylene) is a conducting polymer of the rigid-rod polymer family. PPV is the only polymer of this type that can be processed into a highly ordered crystalline thin film. PPV and its derivatives are electrically conducting upon doping. Although insoluble in water, its precursors can be manipulated in aqueous solution. The small optical band gap and its bright yellow fluorescence makes PPV a candidate in applications such as light-emitting diodes (LED) and photovoltaic devices. Moreover, PPV can be doped to form electrically conductive materials. Its physical and electronic properties can be altered by the inclusion of functional side groups. Preparation PPVs can be synthesized by a variety of methods, the details of which determine purity and molecular weight. The most popular methods proceed via p- xylylene intermediates after a base induced elimination from α,α'-disubstituted para-xylenes. : Other methods Although xyl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
