Characterization of low molecular mass thermosensitive diblock copolymers and their self-assembly by means of analytical ultracentrifugation

The characterization of a series of four poly(N-isopropylacrylamide)-based copolymers with a hydrophilic block of poly(ethylene glycol) with a variable length (MPEG (n) -b-PNIPAAM(71)) has been performed by means of analytical ultracentrifugation. Molecular mass, partial specific volume, sedimentation coefficient (s), and hydrodynamic radius (R (h)) have been determined and successfully compared with other techniques. In addition, the self-assembly process of these four copolymers has been evaluated, finding multimeric species at temperatures lower than low critical solution temperature in the case of the longest copolymer.