| 초록 |
Polymer micelles constructed from a hydrophilic block of poly(ethyleneglycol) (PEG) and a block of poly(N-isopropylacrylamide) (PNIPAM) may have thermosensitive properties in water. Below ~32℃, its lower critical solution temperature (LCST) in water, the polymer is soluble, whereas phase-separation occurs when the temperature is raised above LCST. This hydrophobic character above LCST in water combined with the hydrophilic properties of PEG may lead to thermosensitive micelle-forming. PNIPAM is particularly interesting, as its LCST lies between room temperature and human body temperature. Using cyclotriphosphazene cores, ethyleneglycol-heads of fixed size were formed and by an active site used as initiator for atomic transfer radical polymerization (ATRP) of NIPAM. Due to this controlled polymerization mechanism a low PDI for the PNIPAM-chain and, combined with the fixed size for the ethyleneglycol-heads, a narrow size-distribution for the micelles may be obtained. |
