pK_a is not a constant for amphiphilic polymeric inomers

We synthesized a carboxy-capped tribock copolymer PLGA-PEG-PLGA and found rich phases in its aqueous systems (sol, physical gel, turbid sol, precipitate). The macroscopic phenomena were further interpreted microscopically and mesoscopically. We also confirmed that pK_a was not again a constant in amphiphilic polymers.