Polymers responsive

Okano, Ta Molecular Design of Temperature-Responsive Polymers as Intelligent Materials. Vol, 110, pp. 179-198. 

Figure 2 Schematic representation of glucose-responsive polymer membrane constituted with polyamine membrane and glucose oxidase immobilized membrane. (From Ref. 20.)...

K Ishihara. Synthesis of stimuli responsive polymers and their biomedical applications. PhD Thesis, Waseda Univ, Japan, 1986. 

Some other degradable (i.e., nonvinyl-type) polymers have been reported as components for amphiphilic block copolymers. For example, Hsiue reported the synthesis of a block copolymer of poly(2-ethyl oxazoline) and PLA by ROP. They reported the use of ABA-type triblock copolymers as pH-responsive polymer... 

Many kinds of nonbiodegradable vinyl-type hydrophilic polymers were also used in combination with aliphatic polyesters to prepare amphiphilic block copolymers. Two typical examples of the vinyl-polymers used are poly(/V-isopropylacrylamide) (PNIPAAm) [149-152] and poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) [153]. PNIPAAm is well known as a temperature-responsive polymer and has been used in biomedicine to provide smart materials. Temperature-responsive nanoparticles or polymer micelles could be prepared using PNIPAAm-6-PLA block copolymers [149-152]. PMPC is also a well-known biocompatible polymer that suppresses protein adsorption and platelet adhesion, and has been used as the hydrophilic outer shell of polymer micelles consisting of a block copolymer of PMPC -co-PLA [153]. Many other vinyl-type polymers used for PLA-based amphiphilic block copolymers were also introduced in a recent review [16]. 

Fig. 4. Cyclic change of pH, T, or ionic strength (/) leads to abrupt changes in the drug release rates at certain time intervals in some environmentally responsive polymers.

In the previous sections, we described the overall features of the heat-induced phase transition of neutral polymers in water and placed the phenomenon within the context of the general understanding of the temperature dependence of polymer solutions. We emphasised one of the characteristic features of thermally responsive polymers in water, namely their increased hydropho-bicity at elevated temperature, which can, in turn, cause coagulation and macroscopic phase separation. We noted also, that in order to circumvent this macroscopic event, polymer chemists have devised a number of routes to enhance the colloidal stability of neutral globules at elevated temperature by adjusting the properties of the particle-water interface. 

Laukkanen A (2005) Thermally responsive polymers based on N-vinylcaprolactam and an amphiphilic macromonomer. Academic Dissertation. Yliopistopaino, University of Helsinki, http //ethesis.helsinki.fi/julkaisut/mat/kemia/vk/laukkanen... 

It is known [37,38] that conformational and phase transitions of water-soluble temperature-responsive polymers significantly influence the molecular dynamics of water molecules. Therefore, the studies of temperature dependence of the parameters capable of reflecting such mobility are of signifi-... 

Cammas, S., Suzuki, K., Sone, Y, Sakurai, Y., Kataoka, K., and Okano, T. Thermo-responsive polymer nanoparticles with a core-shell micelle structure as site-specific drug carriers. J. Contr. Rel, 1997,48, 157-164. 

Kikuchi, A. and Okano, T. Temperature-responsive polymers as on-off switches for intelligent biointerfaces, in T. Okano, Ed. Biorelated Polymers and Gels, pp. 1-28. Academic Press, San Diego, CA, 1998. 

The phase transition is directly related to the hydrophilic/hydrophobic balance in a copolymer and controlling the polymer composition provides a highly effective way of tuning the LCST. Another example of responsive polymer libraries was based on the combination of 2-hydroxypropyl acrylate and DMA or A-acryloyl morpholine [50]. The nitroxide mediated copolymerization conditions were chosen on the basis of the kinetic investigation of the homopolymerizations, as discussed in this chapter (see, e.g., Sect. 2.1.2). 

Wax Crystal Control Nanocomposites Stimuli-Responsive Polymers... 

The combined results demonstrate the complexity of the system. Cross-linking must include kinetic contributions to the lateral resistance that are similar to those observed in the networks, but a combination of structural and dynamic factors is likely responsible for the signihcant but opposite effects from kinetically dissimilar cross-links. Stimulus-responsive polymer brush layers hold great potential (Minko et al. 2000 Motornov et al. 2003 Granville et al. 2004 Kaholek et al. 2004a,... 

Kizhakkedathu JN, Norris-Jones R, Brooks DE. Synthesis of well-defined environmentally responsive polymer brushes by aqueous ATRP. Macromolecules 2004 37 734-743. 

Minko S, Stamm M, Goreshnik E, Usov D, Sidorenko A. Environmentally responsive polymer brush layers for switchable surface properties. Pol3mi Mater Sci Eng 2000 83 533-534. 

Motomov M, Minko S, Eichhom KJ, Nitschke M, Simon F, Stamm M. Reversible tuning of wetting behavior of polymer surface with responsive polymer brushes. Langmuir 2003 19 8077-8085. 

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