Alamgir Karim | |
---|---|
Alma mater | St. Stephen's College, Delhi Northwestern University |
Scientific career | |
Institutions | University of Houston |
Thesis | Neutron reflection studies of interdiffusion in polymers (1990) |
Doctoral advisor | Gian P. Felcher |
Other academic advisors | Matthew Tirrell |
Website | Karim Research Group |
Alamgir Karim is a professor of chemical and biomolecular engineering at the University of Houston noted for his work on polymer and polymer nanocomposite materials.
Karim received a B.Sc. degree in physics from St. Stephen's College, Delhi in 1985. He worked under [[]] at Northwestern University, where he received a PhD in physics in 1991. He worked as a postdoctoral research associate under Matthew Tirrell at the University of Minnesota in 1991 -- 1992.
Karim joined the Polymers Division at the National Institute of Science and Technology in 1993, advancing from Physicist to Group Leader. In 2004 he was named a Fellow of the American Physical Society [1] from the Division of Polymer Physics for pioneering research on polymer thin films and interfaces, polymer brushes, blend film phase separation, thin film dewetting, pattern formation in block copolymer films, and the application of combinatoric measurement methods to complex polymer physics. In 2008 he moved to the Department of Polymer Engineering at the University of Akron, where he was the Goodyear Chair Professor. In 2017 he joined the Department of Chemical & Biomolecular Engineering at the University of Houston (UH), where he is the Dow Chair and Welch Foundation Professor.
Karim is an expert in the processing of polymer thin films, [2] polymer brushes [3] block copolymers, [4] polymer blends, [5] and polymer-nanoparticle mixtures. [6] He has applied these materials to produce membranes, [7] phase gratings [8] , and sensors [9] , among other applications.
At UH, he has developed methods to process chitin, [10] increase the energy density of capacitors [11] [12] and manipulate polyelectrolyte coacervate droplets [13] . In 2024 he proposed that coacervate droplets suspended in deionized water could potentially act as protocells for the origins of life. [14]
His most-cited research article demonstrated a method to calculate the elastic moduli of polymer thin films from the spacing of wrinkles on polymer films. [15]
Polyvinylidene fluoride or polyvinylidene difluoride (PVDF) is a highly non-reactive thermoplastic fluoropolymer produced by the polymerization of vinylidene difluoride. Its chemical formula is (C2H2F2)n.
In polymer chemistry, a copolymer is a polymer derived from more than one species of monomer. The polymerization of monomers into copolymers is called copolymerization. Copolymers obtained from the copolymerization of two monomer species are sometimes called bipolymers. Those obtained from three and four monomers are called terpolymers and quaterpolymers, respectively. Copolymers can be characterized by a variety of techniques such as NMR spectroscopy and size-exclusion chromatography to determine the molecular size, weight, properties, and composition of the material.
In fluid mechanics, dewetting is one of the processes that can occur at a solid–liquid, solid–solid or liquid–liquid interface. Generally, dewetting describes the process of retraction of a fluid from a non-wettable surface it was forced to cover. The opposite process—spreading of a liquid on a substrate—is called wetting. The factor determining the spontaneous spreading and dewetting for a drop of liquid placed on a solid substrate with ambient gas, is the so-called spreading coefficient S:
Pentacene is a polycyclic aromatic hydrocarbon consisting of five linearly-fused benzene rings. This highly conjugated compound is an organic semiconductor. The compound generates excitons upon absorption of ultra-violet (UV) or visible light; this makes it very sensitive to oxidation. For this reason, this compound, which is a purple powder, slowly degrades upon exposure to air and light.
In physics, a "coffee ring" is a pattern left by a puddle of particle-laden liquid after it evaporates. The phenomenon is named for the characteristic ring-like deposit along the perimeter of a spill of coffee. It is also commonly seen after spilling red wine. The mechanism behind the formation of these and similar rings is known as the coffee ring effect or in some instances, the coffee stain effect, or simply ring stain.
Coacervate is an aqueous phase rich in macromolecules such as synthetic polymers, proteins or nucleic acids. It forms through liquid-liquid phase separation (LLPS), leading to a dense phase in thermodynamic equilibrium with a dilute phase. The dispersed droplets of dense phase are also called coacervates, micro-coacervates or coacervate droplets. These structures draw a lot of interest because they form spontaneously from aqueous mixtures and provide stable compartmentalization without the need of a membrane—they are protocell candidates.
In materials science, a polymer brush is the name given to a surface coating consisting of polymers tethered to a surface. The brush may be either in a solvated state, where the tethered polymer layer consists of polymer and solvent, or in a melt state, where the tethered chains completely fill up the space available. These polymer layers can be tethered to flat substrates such as silicon wafers, or highly curved substrates such as nanoparticles. Also, polymers can be tethered in high density to another single polymer chain, although this arrangement is normally named a bottle brush. Additionally, there is a separate class of polyelectrolyte brushes, when the polymer chains themselves carry an electrostatic charge.
Small-angle X-ray scattering (SAXS) is a small-angle scattering technique by which nanoscale density differences in a sample can be quantified. This means that it can determine nanoparticle size distributions, resolve the size and shape of (monodisperse) macromolecules, determine pore sizes, characteristic distances of partially ordered materials, and much more. This is achieved by analyzing the elastic scattering behaviour of X-rays when travelling through the material, recording their scattering at small angles. It belongs to the family of small-angle scattering (SAS) techniques along with small-angle neutron scattering, and is typically done using hard X-rays with a wavelength of 0.07 – 0.2 nm. Depending on the angular range in which a clear scattering signal can be recorded, SAXS is capable of delivering structural information of dimensions between 1 and 100 nm, and of repeat distances in partially ordered systems of up to 150 nm. USAXS can resolve even larger dimensions, as the smaller the recorded angle, the larger the object dimensions that are probed.
In polymer chemistry, gradient copolymers are copolymers in which the change in monomer composition is gradual from predominantly one species to predominantly the other, unlike with block copolymers, which have an abrupt change in composition, and random copolymers, which have no continuous change in composition . In the gradient copolymer, as a result of the gradual compositional change along the length of the polymer chain less intrachain and interchain repulsion are observed.
Poly(N-isopropylacrylamide) (variously abbreviated PNIPA, PNIPAM, PNIPAAm, NIPA, PNIPAA or PNIPAm) is a temperature-responsive polymer that was first synthesized in the 1950s. It can be synthesized from N-isopropylacrylamide which is commercially available. It is synthesized via free-radical polymerization and is readily functionalized making it useful in a variety of applications.
Temperature-responsive polymers or thermoresponsive polymers are polymers that exhibit drastic and discontinuous changes in their physical properties with temperature. The term is commonly used when the property concerned is solubility in a given solvent, but it may also be used when other properties are affected. Thermoresponsive polymers belong to the class of stimuli-responsive materials, in contrast to temperature-sensitive materials, which change their properties continuously with environmental conditions. In a stricter sense, thermoresponsive polymers display a miscibility gap in their temperature-composition diagram. Depending on whether the miscibility gap is found at high or low temperatures, either an upper critical solution temperature (UCST) or a lower critical solution temperature (LCST) exists.
An organic solar cell (OSC) or plastic solar cell is a type of photovoltaic that uses organic electronics, a branch of electronics that deals with conductive organic polymers or small organic molecules, for light absorption and charge transport to produce electricity from sunlight by the photovoltaic effect. Most organic photovoltaic cells are polymer solar cells.
Grazing-incidence small-angle scattering (GISAS) is a scattering technique used to study nanostructured surfaces and thin films. The scattered probe is either photons or neutrons. GISAS combines the accessible length scales of small-angle scattering and the surface sensitivity of grazing incidence diffraction (GID).
Harvey Douglas Keith was a physicist and one of the primary polymer researchers over the latter half of the 20th century.
Timothy P. Lodge is an American polymer scientist.
Polymerization-induced phase separation (PIPS) is the occurrence of phase separation in a multicomponent mixture induced by the polymerization of one or more components. The increase in molecular weight of the reactive component renders one or more components to be mutually immiscible in one another, resulting in spontaneous phase segregation.
Frank Steven Bates is an American chemical engineer and materials scientist. Bates is a Regent's Professor (2007–present), a Distinguished McKnight University Professor (1996–present), and department head (1999-2014) in the department of chemical engineering and materials science at the University of Minnesota, where he has been a faculty member since 1989. Prior to his appointment at the University of Minnesota, Bates was a member of the technical staff at AT&T Bell Laboratories from 1982-1989.
Solvent vapor annealing (SVA) is a widely used technique for controlling the morphology and ordering of block copolymer (BCP) films. By controlling the block ratio (f = NA/N), spheres, cylinders, gyroids, and lamellae structures can be generated by forming a swollen and mobile layer of thin-film from added solvent vapor to facilitate the self-assembly of the polymer blocks. The process allows increased lateral ordering by several magnitudes to previous methods. It is a more mild alternative to thermal annealing.
Polysulfobetaines are zwitterionic polymers that contain a positively charged quaternary ammonium and a negatively charged sulfonate group within one constitutional repeat unit. In recent years, polysulfobetaines have received increasing attention owing to their good biotolerance and ultralow-fouling behavior towards surfaces. These properties are mainly referred to a tightly bound hydration layer around each zwitterionic group, which effectively suppresses protein adsorption and thus, improves anti-fouling behavior. Therefore, polysulfobetaines have been typically employed as ultrafiltration membranes, blood-contacting devices, and drug delivery materials.
Cononsolvency is a phenomenon where two solvents that can typically readily dissolve a polymer, when mixed, at certain ratios of these two solvents, are no longer able to dissolve the polymer. This phenomenon is in contrast to cosolvency where two solvents that are both poor at dissolving a material, but when the two poor solvents admixed, can form a mixed solvent capable of dissolving the material.