Water-soluble thermoresponsive polymer

Table 1 The most recent reviews devoted to the water-soluble thermoresponsive polymers...

Thermoresponsive polymers containing short oligo(ethy-lene glycol) side chains have been proposed as an attractive alternative to PNIPAAm. PEG is an uncharged, water-soluble, nontoxic polymer used to prepare biocompatible materials, such as biosensors and dmg delivery systems.Lutz ... 

LUZ Luzon, M., Boyer, C., Peinado, C., Corrales, T., Whittaker, M., Tao, L., and Davis, T.P., Water-soluble, thermoresponsive, hyperbranched copolymers based on PEG-methacrylates Synthesis, characterization, and LCST behavior, J. Polym. Sci. Part A Polym. Chem., 48, 2783, 2010. 

Another approach involves the covalent attachment of a metal complex to a (water-) soluble polymer [41]. By using thermoresponsive, smart , polymers the reaction can be performed in a homogeneous liquid phase and, after completion, the polymer-enlarged catalyst can be precipitated by adjusting the temperature [42]. 

As discussed previously, zwitterionic polymers such as poly (sulfobetaine)s have thermoresponsive UCST properties. The water solubility of poly(sulfobetaine) depends on salt concentration. The site-binding ability of the cation and the anion allows polymer chains to preferentially complex the... 

The years 2006-2008 were the most productive in terms of the number of reviews on amphiphilic polymers. Over ten detailed reviews on thermoresponsive water-soluble polymers were published in English in 2006 [1]. In Table 1 we list the reviews to date that are the most related to the scope of the current review and, from our point of view, those that fully cover all aspects of thermoresponsive polymers. The key phrases in the table are not just the key words given by the authors, but rather the highlights of the contents. 

The polymer architecture affects the demixing behaviour of thermoresponsive polymers [562], On the basis of theoretical studies it is expected that, as a rule, branched macromolecules are more soluble than their linear analogues [563-565]. This prediction was confirmed experimentally in the case of a solution of star-like polystyrene in cyclohexane (an UCST-type phase separation) for which an increase in the degree of branching resulted in a decrease in the temperature of demixing [566, 567], On the basis of a review of water-soluble polymers of various shapes by Aoshima and Kanaoka [30], it appears that water-soluble polymers do not offer a uniform tendency in their LCST-type phase behaviour. 

Wong and coworkers have investigated the enzymatic oligosaccharide synthesis on a thermoresponsive polymer support (Scheme 16.33). The copolymers of 7V-/-propyla-crylamide (NIPAm) and functionalized monomers are thermoresponsive and exhibit inverse temperature-dependent solubility in water they are soluble in cold water but become... 

PNIPAAm is a widely studied thermoresponsive polymer that exhibits a lower critical solution temperature (LCST) [51, 52]. Below the LCST, the polymer is expanded and hydrophihc and is thus soluble in water. Above this critical temperature, there is an abrupt phase transition leading to a collapsed and hydrophobic polymeric structure, which renders the polymer insoluble in water [53-55]. The LCST of... 

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