posted on 2017-08-01, 18:36authored bySarah
L. Canning, Thomas J. Neal, Steven P. Armes
Polymerization-induced
self-assembly (PISA) is used for the highly
convenient and efficient preparation of ampholytic diblock copolymer
nanoparticles directly in acidic aqueous solution. Cationic nanoparticles
comprising a protonated polyamine stabilizer block and a hydrophobic
polyacid core-forming block are formed at pH 2. Micelle inversion
occurs at pH 10 to produce anionic nanoparticles with an ionized polyacid
stabilizer block and a hydrophobic polyamine core-forming block. Macroscopic
precipitation occurs at around pH 6–7, which lies close to
the isoelectric point of this ampholytic diblock copolymer. Incorporation
of fluorescein and rhodamine dye labels into the acid and amine blocks,
respectively, leads to dual-color bifluorescent self-reporting pH-responsive
nanoparticles.