Abstract Atom transfer radical polymerization (ATRP) is a robust method for the preparation of well‐defined (co)polymers. This process has also enabled wide range polymer brushes where (co)polymers are covalently attached to either curved or flat surfaces. In this review, general methodology synthesis from surfaces, polymers and colloids summarized focusing on reports using ATRP. Additionally, morphology ultrathin films discussed atomic force microscopy (AFM) other techniques confirm...

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTNanocages Derived from Shell Cross-Linked Micelle TemplatesHaiyong Huang, Edward E. Remsen, Tomasz Kowalewski, and Karen L. WooleyView Author Information Department of Chemistry, Washington University One Brookings Drive, St. Louis, Missouri 63130 Monsanto Company, 800 N. Lindbergh Boulevard, 63167 Cite this: J. Am. Chem. Soc. 1999, 121, 15, 3805–3806Publication Date (Web):April 3, 1999Publication History Received14 October 1998Published...

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTWater-Soluble Knedel-like Structures: The Preparation of Shell-Cross-Linked Small ParticlesK. Bruce Thurmond, Tomasz Kowalewski, and Karen L. WooleyView Author Information Department Chemistry, Washington University St. Louis, Missouri 63130 Cite this: J. Am. Chem. Soc. 1996, 118, 30, 7239–7240Publication Date (Web):July 31, 1996Publication History Received19 April 1996Published online31 July inissue 1 January...

Low polydispersity regioregular polythiophenes with number average molecular weights ranging from 2 to 13 kDa were cast under the same conditions solution form a series of field effect transistors (FETs). Tapping mode AFM and grazing incidence small-angle X-ray scattering revealed that in all cases polymers formed regular nanofibrillar morphologies width nanofibrils proportional weight contour length polymer chains, indicating conjugated backbones oriented perpendicular nanofibril axes. FET...

Self-healing polymeric materials with branched architectures and reversible cross-linking functionalities at the periphery of branches were synthesized by atom transfer radical polymerization (ATRP). Poly(n-butyl acrylate) grafted star polymers prepared chain extension ATRP from cross-linked cores comprised poly(ethylene glycol diacrylate). These further used as macroinitiators for consecutive bis(2-methacryloyloxyethyl disulfide) (DSDMA), in which way disulfide cross-links (SS) introduced...

ABCA1 is an ATP-binding cassette protein that transports cellular cholesterol and phospholipids onto high density lipoproteins (HDL) in plasma. Lack of humans mice causes abnormal lipidation increased catabolism HDL, resulting very low plasma apoA-I, apoA-II, HDL. Herein, we have used Abca1-/- to ask whether involved HDL the central nervous system (CNS). ApoE most abundant CNS apolipoprotein present HDL-like CSF. We found greatly decreased apoE levels both cortex (80% reduction) CSF (98%...

Simply changing the solvent or evaporation conditions enables physical properties of polythiophene block copolymers and polyurethane elastomers to be controlled. The all have high conductivities as well excellent film-forming good mechanical properties, well-defined nanowires that reach lengths in micron range can formed (see atomic force microscopy image).

We have applied in situ atomic force microscopy to directly observe the aggregation of Alzheimer’s β-amyloid peptide (Aβ) contact with two model solid surfaces: hydrophilic mica and hydrophobic graphite. The time course was followed by continuous imaging surfaces remaining 10–500 μM solutions Aβ PBS (pH 7.4). Visualization fragile nanoscale aggregates made possible application a tapping mode imaging, which minimizes lateral forces between probe tip sample. size shape aggregates, as well...

Reversible disruption and regeneration of block-copolymer micelles has been achieved by UV visible-light irradiation studied atomic force microscopy (see picture). A hydrophobic dye encapsulated in the original polymeric was released after irradiation. Remarkably, some re-encapsulated on with visible light.

Novel nanoporous nitrogen-enriched carbon materials were prepared through a simple carbonization procedure of well-defined block copolymer precursors containing the source carbon, i.e., polyacrylonitrile (PAN), and sacrificial block, poly(n-butyl acrylate) (PBA). The preparation nanocarbons with hierarchical pore structure was enabled by high fidelity preservation initial phase-separated nanostructure between two polymer blocks upon carbonization. Supercapacitors fabricated from carbons...

A semiconducting polymer bearing the thiazolothiazole moiety in polythiophene backbone (see figure) is synthesized. The found to have small bandgap and large ionization potential. Despite low molecular weight, exhibited a high field-effect mobility after annealing. on/off ratio suggests possesses stability against oxygen doping. device also showed good environmental stability.

Owing to their superior transport properties, poly(alkylthiophenes) and derivatives emerged as one of the most widely studied semiconducting polymers with potential applications in organic electronics. It is now generally acknowledged that particularly effective ways increase carrier mobility these materials by increasing length conjugated backbones. Some recent reports suggest also mobilities can be further enhanced highly crystalline arrangement (and interdigitation) alkyl side chains...

Shell cross-linked knedels (SCK's), nanometer-sized spherical particles that are composed of a core-shell morphology, were prepared by intramicellar polymerization side chain functionalities along the backbone hydrophilic block amphiphilic polystyrene-b-poly(vinylpyridine) copolymers organized into micellar assemblies. Control over size SCK's was demonstrated through variation chemistry and processing conditions. The solid-state SCK diameters (from atomic force microscopy) ranged from 8 to...

The synthesis of hybrid nanoparticles was conducted by the atom transfer radical polymerization (ATRP) styrene and (meth)acrylates from colloidal surfaces. Colloidal initiators were prepared functionalization silica colloids with 2-bromoisobutyrate groups. ATRP surfaces then performed to attach well-defined homopolymers block copolymers an inorganic core. Kinetics (Sty), n-butyl acrylate (BA), methyl methacrylate (MMA) under identical reaction conditions investigated. Hybrid containing...

Arrays of graphitic carbon nanoclusters were obtained by pyrolysis nanoscale phase-separated block copolymers polyacrylonitrile and poly(n-butyl acrylate). Upon heating in an inert atmosphere to temperatures ranging from approximately 400 1200 degrees C, domains converted into nanoclusters, maintaining the overall shape spacing, whereas acrylate) phase was sacrificed. Preservation original morphology a copolymer possible only if preceded oxidation at 230 analogy with thermal stabilization...

A series of novel electroactive and photoactive conjugated copolymers based on N-alkyl dithieno[3,2-b:2',3'-d]pyrroles (DTP) thiophene (TH) units (DTP-co-THs) were synthesized using a Stille coupling reaction exhibited molecular weights 1.6 x 10(4) to 5.0 g/mol. The incorporation soluble substituted thiophenes planar DTP resulted in low band gap, highly conductive polymers. DTP-co-THs excellent solubility common organic solvents formed high-quality films. Optical characterization revealed...

Antimicrobial surfaces were prepared using the "grafting onto" technique. Well-defined block copolymers containing poly(2-(dimethylamino)ethyl methacrylate) and poly(3-(trimethoxysilyl)propyl segments (PDMAEMA/PTMSPMA) corresponding random via atom transfer radical polymerization (ATRP), followed by covalent attachment to a glass surface through reaction of trimethoxysilyl groups with silanol groups. The density quaternary ammonium (QA) available bind small molecules in solution increased...

A novel method was developed to prepare shell-cross-linked knedel-like structures (SCK's), which are double-layered polymer nanospheres, in a convenient three-step procedure: (1) polystyrene-b-poly(acrylic acid) ((DPn)PS = 130, (DPn)PAA 120) copolymer prepared by sequential anionic polymerization of styrene and tert-butyl acrylate, followed hydrolysis; (2) the amphiphilic block allowed self-assemble into spherical multimolecular micelles water THF solvent mixture; (3) poly(acrylic acid),...

ADVERTISEMENT RETURN TO ISSUECommunication to the...Communication the EditorNEXTConducting Regioregular Polythiophene Block Copolymer Nanofibrils Synthesized by Reversible Addition Fragmentation Chain Transfer Polymerization (RAFT) and Nitroxide Mediated (NMP)Mihaela C. Iovu, Rockford Craley, Malika Jeffries-EL, Ashley B. Krankowski, Rui Zhang, Tomasz Kowalewski, Richard D. McCulloughView Author Information Carnegie Mellon University, Chemistry Department, 4400 Fifth Avenue, Pittsburgh,...

Large-scale alignment of lamellae in thin films diblock copolymers containing polyacrylonitrile and poly(n-butyl acrylate) was achieved by casting copolymer solution on a silicon substrate moved away at constant speed from the nozzle (zone-casting). Grazing incidence small-angle X-ray scattering revealed that lamellae, which were perpendicular to substrate, also aligned over macroscopic scale direction direction. Such long-range ordered block then converted pyrolysis into nanostructured...

A novel synthetic route to polymer-coated ferromagnetic colloids of metallic cobalt has been developed. Well-defined end-functional polystyrenes were synthesized using controlled radical polymerization and used as surfactants in the thermolysis dicobaltoctacarbonyl afford uniform nanoparticles. The presence polymer shell enabled prolonged colloidal stability dispersions a wide range organic solvents formed glassy encapsulating coatings around cores solid state. These assembled into robust,...

Regioregular polythiophene-based conductive copolymers with highly crystalline nanostructures are shown to hold considerable promise as the active layer in volatile organic compound (VOC) chemresistor sensors. While regioregular polythiophene polymer chain provides a charge conduction path, its chemical sensing selectivity and sensitivity can be altered either by incorporating second form block copolymer or making random of different alkyl side chains. The were exposed variety VOC vapors,...

Tapping-mode atomic force microscopy was used to study the radial deformability of a multiwalled carbon nanotube (MWCNT). By imaging MWCNT under different tapping forces, we were able demonstrate its remarkable reversible (up approximately 40%) and reveal internal discontinuities along length. The values effective elastic modulus several sections in direction estimated with Hertz model.

Mesoporous carbons were synthesized from polyacrylonitrile (PAN) using ordered and disordered mesoporous silica templates characterized transmission electron microscopy (TEM), powder X-ray diffraction, nitrogen adsorption, thermogravimetry. The pores of the infiltrated with carbon precursor via polymerization acrylonitrile initiation sites chemically bonded to surface. This method is expected allow for a uniform filling template PAN minimize introduction nontemplated PAN, thus mitigating...