نتایج جستجو برای: block copolymer

تعداد نتایج: 167435  

2014
Marcus Müller Weihua Li Juan Carlos Orozco Ulrich Welling

Chemically patterned surfaces have been successfully employed to direct the kinetics of self-assembly of block copolymers into dense, periodic morphologies (”chemoepitaxy”). Significant efforts have been directed towards understanding the kinetics of structure formation and, particularly, the formation and annihilation of defects. In the present manuscript we use computer simulations of a soft,...

2017
Sanjun Niu Ravi F. Saraf

One way to produce high order in a block copolymer thin film is by solution casting a thin film and slowly evaporating the solvent in a sealed vessel. Such a solvent-annealing process is a versatile method to produce a highly ordered thin film of a block copolymer. However, the ordered structure of the film degrades over time when stored under ambient conditions. Remarkably, this aging process ...

2017
Philip J. Costanzo Frederick L. Beyer

Thermally responsive bulk polymer films utilizing reversible Diels-Alder chemistry have been developed. Gold nanoparticles (AuNPs) were passivated with thiol-terminated poly(styrene)-b-poly(ethylene glycol) (PS-b-PEG) copolymer ligand, where the PS and PEG blocks are joined via a Diels-Alder (DA) linkage. The ligand-functionalized nanoparticles were dispersed within a microphase-separated PS-b-...

2017
Matthew J Derry Oleksandr O Mykhaylyk Steven P Armes

Diblock copolymer vesicles are prepared via RAFT dispersion polymerization directly in mineral oil. Such vesicles undergo a vesicle-to-worm transition on heating to 150 °C, as judged by TEM and SAXS. Variable-temperature 1 H NMR spectroscopy indicates that this transition is the result of surface plasticization of the membrane-forming block by hot solvent, effectively increasing the volume frac...

2017
Seong Min Lee Woo-Dong Jang

BACKGROUND Polymeric micelles attract great attention in drug delivery and therapeutics. Various types of block copolymers have been designed for the application in biomedical fields. If we can introduce additional functional groups to the block copolymers, we can achieve advanced applications. In this regards, we tried to introduce aggregation induced emission enhancement (AIE) unit in the blo...

2017
Janusz Nowicki Julia Woch Małgorzata Mościpan Andrzej Robaszkiewicz Rafał Grabowski Izabela Semeniuk Karol Erfurt

The synthesis of selected polyoxyethylene-polyoxypropylene block copolymer (poloxamer) fatty acid monoesters is presented. Organotin homogeneous catalyst Sn bis(2-ethylhexanoate) effectively catalyzed the esterification reaction of (EO)-(PO)-(EO) block copolymer (poloxamer) with fatty acids. The reaction proceeded in high yield and high selectivity to monoesters. Content of diesters in final pr...

2000
A. N. Morozov J. G. E. M. Fraaije

The Leibler theory [L. Leibler, Macromolecules 13 1602 (1980)] for mi-crophase separation in AB block copolymer melts is generalized for systems with arbitrary topology of molecules. A diagrammatic technique for calculation of the monomeric correlation functions is developed. The free energies of various mesophases are calculated within the second-harmonic approximation. Model highly-branched t...

Journal: :RSC advances 2014
Yanda Lei Tongxin Wang James W Mitchell Lynette Zaidel Jianhong Qiu LaTonya Kilpatrick-Liverman

Inspired by the fact that certain natural proteins, e.g. casein phosphopeptide or amelogenin, are able to prevent tooth erosion (mineral loss) and to enhance tooth remineralization, a synthetic amphiphilic diblock copolymer, containing a hydrophilic methacryloyloxyethyl phosphate block (MOEP) and a hydrophobic methyl methacrylate block (MMA), was designed as a novel non-fluoride agent to preven...

Journal: :Langmuir : the ACS journal of surfaces and colloids 2004
Luisa Andruzzi Alexander Hexemer Xuefa Li Christopher K Ober Edward J Kramer Giancarlo Galli Emo Chiellini Daniel A Fischer

Surface-grafted styrene-based homopolymer and diblock copolymer brushes bearing semifluorinated alkyl side groups were synthesized by nitroxide-mediated controlled radical polymerization on planar silicon oxide surfaces. The polymer brushes were characterized by X-ray photoelectron spectroscopy (XPS), near-edge X-ray absorption fine structure (NEXAFS), and time-dependent water contact angle mea...

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