Vinyl ethers, oxyethylene pendants

The pendant functions listed in Figure 3 are often useful and of synthetic interest per se. For example, methacrylate and acrylate esters are polymerizable (cross-linking sites) [19-21] the cinnamate is photorespon-sive (for the photo-induced dimerization of its unsaturated groups) [20] oligo(oxyethylene) [25-27] and carbohydrate groups [35] give hydrophilic and water-soluble polymers, whereas perfluoroalkyl moieties [32-34] enhance hydrophobicity. Thus, poly(vinyl ethers) with cinnamate functions... 

Polyi v mylether)s °- o3-r 33 X Polyether is a polymer with oxygen atoms in the main or side chtiin. Among them, thermoresponsive poly(vinylether)s have oxymethylene and/or oxyethylene pendants in their side chains [30, 124,404-406] Phase separation temperature of vinyl ethers can be controlled by varying the number of the pendant oxyethylene units and/or the hydrophobicity of an co-alkyl group, R Tcp measurements typically reveal an abrupt reversible transition within AT = 1°C no hysteresis Homopolymers of ethyl vinylether and higher alkyl vinylethers are insoluble in water... 

Aoshima, S., Oda, H. and Kobayashi, E. (1992) Synthesis of thermally-induced phase separating polymer with well-defined polymer structure by living cationic polymerization. I. Synthesis of poly(vinyl ether)s with oxyethylene units in the pendant and its phase separation behavior in aqueous solution, / PoZym Sci Part A Polym Chem, 30,2407-2413, doi 10.1002/pola.l992.080301115. 

Fig.1 Structures of M-isopropylacrylamide (NIPAM) and vinyl ethers with oxyethylene pendants...

The thermoresponsive properties of poly(vinyl ether)s with oxyethylene pendants (60) in water were discovered about 20 years ago [217-219]. This phase transition was not only highly sensitive but also completely reversible on heating and cooling, without hysteresis. Clear aqueous solutions of these polymers rapidly transformed into turbid solutions, with complete transition within 1 °C. This was also the case for the reverse transition. For example, an aqueous solution of a polymer (60a) (Fig. 11) obtained from 2-ethoxy-ethyl vinyl ether (EOVE) imderwent phase separation sensitively at 20 °C. A systematic survey revealed that the phase separation temperature (Tps) of poly(vinyl ether)s with oxyethylene pendants can be controlled by varying... 

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