Solution Properties of Polysarcosine: From Absolute and Relative Molar Mass Determinations to Complement Activation

Polysarcosine (pSar) was one of the first polymers synthesized in a controlled living manner, but it was only recently when it was reconsidered as a promising alternative for poly(ethylene glycol) (PEG) in biomedical applications. Despite receiving more and more attention, very little is known about the solution properties of pSar, such as coil dimensions and thermodynamic interactions. In this article, we report on these properties of pSar with degrees of polymerization 50 < Xn < 400 that were prepared by controlled living ring-opening polymerization. The polymers are characterized by gel permeation chromatography (GPC), MALDI-TOF mass spectrometry, dynamic and static light scattering (SLS), and viscometry. The chain stiffness of pSar in PBS in terms of the Kuhn statistical segment length, lk, was estimated to lk = 1.5 nm by application of the Yamakawa–Fujii wormlike chain theory to the experimentally determined hydrodynamic radii, Rh, thus being higher than lk = 1.1 nm for PEG in PBS. Also, the second v...