Thermal Field-Flow Fractionation with Quintuple Detection for the Comprehensive Analysis of Complex Polymers

With a constantly increasing complexity of macromolecular structures, advanced polymer analysis faces new challenges with regard to the comprehensive analysis of these structures. Today it goes without saying that comprehensive polymer analysis requires selective and robust fractionation methods in combination with a set of information-rich detectors. Thermal field-flow fractionation (ThFFF) has proven to be a powerful technique for the fractionation of complex polymers as well as polymer assemblies. In the present study, ThFFF is coupled to a set of five detectors to simultaneously provide quantitative information on a number of important molecular parameters, including molar mass, molecular size, chemical composition, molecular topology, intrinsic viscosity, and normal and thermal diffusion coefficients. The five-detector setup includes a triple detector device (multiangle light scattering (MALS), differential refractive index (dRI), and differential viscometer (dVis)) that is coupled to an ultraviolet (UV) detector for dual concentration detection and an online dynamic light scattering (DLS) detector. Triple detection consisting of MALS, dRI, and dVis provides information on molar mass, molecular size, and molecular topology. Dual concentration detection offers compositional analysis from a combination of UV and dRI detectors, whereas DLS provides information on diffusion coefficients and hydrodynamic radii. The power of this novel quintuple detector ThFFF (ThFFF-QD) is documented for three important fields of application, namely, the comprehensive analysis of (1) linear and star-shaped polymers, (2) hydrogenated and deuterated polymers, and (3) block copolymer self-assemblies. These applications highlight the novel approach of determining the most relevant molecular parameters, including Mark-Houwink and conformation plots, simultaneously in a single experiment.