The synthetic polymer cannot be completely monodisperse; molecular weight distribution (MWD) is the basic characteristic of polymers. Jiandong Ding’s group took amphiphilic copolymer  Poly(D,L-lactide-co-glycolide)-b-poly(ethylene glycol)-b-poly(D,L-lactide-co-glycolide) (PLGA-PEG-PLGA) as the example, a series of PLGA-PEG-PLGA with different MWDs under similar weight-average molecular weight (Mw) or number-average molecular weight (Mn) were obtained via step precipitation and mixing of synthesized copolymers with a given PEG length and varied PLGA lengths. The effect of MWD on micellization and thermogelling of copolymers aqueous solution were investigated. It was found that MWD has great impact on self-assembly behavior of polymers, and this effect cannot be interpreted by a simple addition of MW effects. This study revealed that non-monodispersity is not a flaw of polymers; MWD is an independent and important regulator of the condensed state of polymers. 

The article with Liang Chen, a PhD student supervised by Professor Ding as the first author was published in Macromolecules. For details: Liang Chen, Tianyuan Ci, Ting Li, Lin Yu, and Jiandong Ding*, Effects of molecular weight distribution of amphiphilic block copolymers on their solubility, micellization and temperature-induced sol-gel transition in Water. Macromolecules, 2014, 47, 5895−5903. Article links：http://pubs.acs.org/doi/ipdf/10.1021/ma501110p.