Polypeptide-block-polyesters

Studies of microphase separation have been made on many regular block copolymers containing crystallizable blocks. The types of crystallizable blocks which have been examined include poly-ethers, " polyamides/ " polypeptides and polyesters. 

The principal mechanism of temperature-sensitive polymers is the sharp transition from coil to globule in water on heating, indicating a change from a hydrophilic state (coil) below the lower critical solution temperature (LCST) to a hydrophobic state (globule) above the LCST. Representative temperature-sensitive polymers include A -isopropylacrylamide (NIPAAm), its copolymers (LCST 30-50°C) [108, 124-127], polyester block copolymers (20-100°Q [97, 128], and elastin-like polypeptides (27-40°C) [129-131]. To achieve both spatial and temporal control in conjunction with local temperature increases (2-5°C), the LCST of a given polymer can be tailored through its comonomer composition, hydrophilic-hydrophobic balance, stereochemistry [125-127,132], and the addition of salts and surfactants [133]. These thermosensitive polymers with controlled LCSTs (around body temperature) can be applied to specific applications (e.g., tumor treatment). 

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