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Stimuli-responsive Polymers (stimuli-responsive + polymer)

Distribution by Scientific Domains
Polymers and Materials Science80%

Selected Abstracts

Conformational effects on the performance and selectivity of a polymeric pseudostationary phase in electrokinetic chromatography

ELECTROPHORESIS, Issue 4-5 2005
Jonathan P. McCarney
Abstract The effect of the conformation of a polymeric pseudostationary phase on performance and selectivity in electrokinetic chromatography was studied using an amphiphilic pH-responsive polymer that forms compact intramolecular aggregates (unimer micelles) at low pH and a more open conformation at high pH. The change in conformation was found to affect the electrophoretic mobility, retention, selectivity, and separation efficiency. The low-pH conformer has higher electrophoretic mobility and greater affinity for most solutes. The unimer micelle conformation was also found to provide a solvation environment more like that of micelles and other amphiphilic self-associative polymers studied previously. It was not possible to fully characterize the effect of conformation on efficiency, but very hydrophobic solutes with long alkyl chains appeared to migrate with better efficiency when the unimer micelle conformation was employed. The results imply that polymers with a carefully optimized lipophilic-hydrophilic balance that allow self-association will perform better as pseudostationary phases. In addition, the results show that electrokinetic chromatography is a useful method for determining the changes in solvation environment provided by stimuli-responsive polymers with changes in the conditions. [source]

Multifunctional Magnetic Optical Sensor Particles with Tunable Sizes for Monitoring Metabolic Parameters and as a Basis for Nanotherapeutics

ADVANCED FUNCTIONAL MATERIALS, Issue 11 2010
Günter Mistlberger
Abstract Magnetic optical sensor particles with multifunctional cores and shells are synthesized via a facile nanoprecipitation method and the subsequent modification of the particle shell. The hydrophobic particle core includes optical oxygen indicators, a light harvesting system, photosensitizers, and magnetic nanoparticles. Further functionalities are introduced by modifying the shell with enzymes, antibodies, multiple layers of polyelectrolytes, stimuli-responsive polymers, and luminescent indicator dyes. The hydrodynamic diameter is tunable by varying different precipitation parameters. [source]

Multiresponsive PEDOT,Ionic Liquid Materials for the Design of Surfaces with Switchable Wettability

ADVANCED FUNCTIONAL MATERIALS, Issue 20 2009
Markus Döbbelin
Abstract Among the different types of stimuli-responsive polymers, conjugated polymers reveal unique multiresponsive behavior. In this work, the synthesis and characterization of new functional poly(3,4-ethylenedioxythiophenes) (PEDOT) bearing imidazolium ionic-liquid moieties (PEDOT-Im) is reported. PEDOT-Im polymers show multiresponsive properties to a variety of stimuli, such as temperature, pH, oxidative doping, and presence of anions. These stimuli provoke different changes in PEDOT-Im, such as changes in color, oxidation state, and, wetting behavior. In all cases, a reversible effect is observed, and the polymers reveal responsive properties in solution as well as in the form of thin films. Whereas sensitiveness to pH and oxidative doping are known phenomena for other PEDOT derivatives, responsiveness to temperature and to anions is a unique property of PEDOT-Im. The anion exchange is further investigated by means of the Quartz Crystal Microbalance with dissipation. Anion exchanges induce fast, adjustable, and reversible contact angle changes between 24° and 107°. As a potential application, surfaces with switchable wettability triggered by anion solutions are prepared by spin-coating PEDOT-Im films onto different substrates. [source]

Immobilization: Reversible Immobilization onto PEG-based Emulsion-templated Porous Polymers by Co-assembly of Stimuli Responsive Polymers (Adv. Mater.

ADVANCED MATERIALS, Issue 1 2009
1/2009)
Reversible immobilization onto the surface of highly porous polymers through co-assembly of stimuli-responsive polymers is reported on p. 55 by Neil Cameron and co-workers. Elastin-based side-chain polymers (EBPs) are prepared by RAFT polymerization and attached to the surface of PEG-based emulsion-templated porous polymers. By careful choice of EBP molecular weight and experimental conditions, pH-controlled reversible co-assembly of a complementary EBP from solution is demonstrated. [source]

Reversible Immobilization onto PEG-based Emulsion-templated Porous Polymers by Co-assembly of Stimuli Responsive Polymers,

ADVANCED MATERIALS, Issue 1 2009
Francisco Fernández-Trillo
Reversible immobilization onto the surface of highly porous polymers through the co-assembly of stimuli-responsive polymers is explored (see figure). Elastin-based side-chain polymers (EBPs) are prepared by RAFT and attached to the surface of PEG-based emulsion-templated porous polymers, leading to a responsive surface capable of pH-controlled reversible immobilization. [source]