Temperature-responsive polymeric

TAK Takeda, N., Nakamura, E., Yokoyama, M., and Okano, T., Temperature-responsive polymeric carriers incorporating hydrophobic monomers for effective transfection in small doses, J. Control. Release, 95, 343, 2004. 

Yokoyama, M. (2002) Gene Delivery Using Temperature-Responsive Polymeric Carriers, Drug Disc. Today, 7, 426-32. 

Agut, W., Brulet, A., Schatz, C., Taton, D., Lecommandoux, S. (2010). pH and temperature responsive polymeric micelles and polymersomes by self-assembly of poly(2-(dimethyl-amino)ethyl methacrylate)-b-poly(glutamic acid) double hydrophilic block copolymers. 

A cleavable, temperature-responsive polymeric cross-linker was utilized by Xu and cowoikers [111] to stabilize micelles from PEO-b-PAPMA-b-poly((Af,Af-diisopropylamino)ethyl methacrylate) triblock copolymer. The PNIPAm cross-linker contained activated ester end groups that were reacted with the primary amines on the PAPMA middle block. The trithiocarbonate moiety located at the middle of PNIPAm cross-linker could then be degraded by aminolysis to break the cross-links. Temperature-responsive micelles and vesicles from diblock and triblock copolymers were shell cross-linked via interpolyelectrolyte complexation [108, 112]. The cross-links formed by the electrostatic interactions of oppositely charged polyelectrolytes could be disrupted by the addition of SME. 

The ability to manipulate reactor temperature profile in the polymerization tubular reactor is very important since it directly relates to conversion and resin product properties. This is often done by using different initiators at various concentrations and at different reactor jacket temperature. The reactor temperature response in terms of the difference between the jacket temperature and the peak temperature (0=Tp-Tj) is plotted in Figure 2 as a function of the jacket temperature for various inlet initiator concentrations. The temperature response not only depends on the jacket temperature but also, for certain combinations of the variables, it is very sensitive to the jacket temperature. 

From this perspective, temperature-responsive hydrogels are reviewed as agents in the design of effective polymeric structures for thermo-responsiveness as Intelligent Materials . 

Chung et al. (1999) measured ADR release from thermo-responsive micelles at various temperatures through the micelle LCST using LTV absorbance at 485 nm in a time-course. The results of the ADR release from the thermo responsive micelles can be referred to the discussion of thermo responsive polymeric micelles by Chung et al. (1999) in the section of pharmaceutical applications. 

In recent years, many kinds of temperature-responsive PNIPAAm and its copolymer hydrogels with other acrylic monomers have been synthesized [142]. Besides being used for hydrogels, NIPAAm monomer can be grafted on to polymer substrates by electron beam, irradiation or UV-initiated graft polymerization to achieve special modification of polymer surfaces. Thus NIPAAm has been grafted on porous polymer films such as LDPE, PP, or polyamide films in order to prepare novel films for pervaporation of liquid mixtures or separation membranes [150,151]. 

The dual-responsive hollow polymeric microspheres, which could be responsive simultaneously to two environmental stimuli, are expected to be more suitable for the controlled release of drugs. For example, the pH and temperature dual-responsive hollow polymeric microspheres could be responsive to the pH and temperature changes in their environment. Temperature-responsive outer shell and pH-responsive inner shell that encapsulate magnetic nanoparticles are widely used for the delivery of therapeutic compounds to the targeting specific sites. 

Additionally, McCormick et al. utilized imine bonds for the preparation of reversible imine SCL micelles. They synthesized a temperature-responsive triblock copolymer, a-methoxypoly(elhylene oxide)- -poly(A-(3-aminopropyl) methacryIamide)-fc-poly((V-isopropyIaCTyIamide) (mPEO-PAPMA-PNIPAM), via aqneons RAFT polymerization. By inCTeasing the solution temperature above the LCST of the PNIPAM block, the polymers self-assembled into micelles. Subsequently, the PAPMA shell was cross-linked with terephthaldicarboxaldehyde to generate SCL micelles with cleavable imine linkages (Figure 54.16). 

Huang, J. Cusick, B. Pietrasik, J. Wang, L. Kowalewski, T. Lin, Q. Matyjaszewski, K. Synthesis and in situ atomic force microscopy characterization of temperature-responsive hydrogels based on poly(2-(dimethylamino)ethyl methacrylate) prepared by atom transfer radical polymerization. Langmuir 2007, 23 (1), 241-249. 

Convertine, A.J. Lokitz, B.S. Vasileva, Y. Myrick, L.J. Scales, C.W. Lowe, A.B. McCormick, C.L. Direct synthesis of thermally responsive DMA/NIPAM diblock and DMA/NIPAM/DMA triblock copolymers via aqueous, room temperature RAFT polymerization. Macromolecules 2006, 39 (5), 1724-1730. 

Thermal Expansion Coefficients. The thermal expansion of a lossy film should be observed as a steady decrease in frequency. The coated devices we studied exhibited a steady frequency shift with temperature. If this change In frequency Is the result of film expansion,then the slope of this frequency curve should be proportional to the thermal expansion coefficient. The T of polymeric materials can be Identified by the change In the thermal expansion coefficient at the T. To verify the effect of surface coating coverage on observed SAW frequency-temperature response behavior, the results for the airbrush-applied films studied here must be compared with results obtained from contiguous films of known thickness. 

Hufendiek A, Trouillet V, Meier MA, Bamer-Kowollik C (2014) Temperature responsive cellulose-gr< -copolymers via cellulose functionalization in an iraric liquid and RAFT polymerization. Biomacromolecules 15 2563-2572... 

INFLUENCE OF TORSIONAL STIFFNESS UPON TEMPERATURE RESPONSE OF A POLYMERIC CHAIN. 

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