Scaling laws between the hydrodynamic parameters and molecular weight of linear poly(2-ethyl-2-oxazoline)

Abstract

Poly(2-ethyl-2-oxazoline) (PEtOx), as an alternative polymer to poly(ethylene glycol), has potential applications in biomedical fields. The hydrodynamic parameters, such as the hydrodynamic radius and sedimentation coefficient, are important to understand its dynamics and properties, including its effect on the interactions between proteins and cells. In this study, we have investigated the hydrodynamic properties and thermodynamic parameters of a series of narrowly distributed PEtOx polymers with molecular weights ranging from 1.3 × 10³ to 3.1 × 10⁵ g mol⁻¹, and the scaling laws between them by the use of a combination of analytical ultracentrifugation and laser light scattering. It is found that the sedimentation coefficient (s_20,w) and hydrodynamic radius (R_h,0) at infinite dilution scale with molecular weight (M_w) as s_20,w = K_s × M^α_w = 0.0071 (S) × M^0.462±0.019_w and R_h,0 = K_Rh × M^β_w = 0.0179 (nm) × M^0.539±0.012_w, respectively.