Molar mass characterization of hydrophilic copolymers, 2 Size exclusion chromatography of cationic (meth)acrylate copolymers

Abstract

A robust and reproducible method for the molar mass analysis of cationic copolymers based on dimethylaminoethyl methacrylate or trimethylammonioethyl methacrylate and different (meth)acrylates has been developed. Size exclusion chromatography (SEC) using a novel polyester-based packing as the stationary phase and dimethylacetamide (DMAC) as the mobile phase yields highly accurate results for copolymers with an amino comonomer content up to 50 wt.-%. To suppress the different polar and ionic interactions between sample molecules, stationary phase and eluent, DMAC was modified with LiBr and tris(hydroxymethylamino)methane (TRIS). Calibrating the SEC system with poly(methyl methacrylate) of narrow polydispersity, molar masses were obtained that are in good agreement with viscosity data. Reproducibility and robustness of the novel method were proven by running samples for an extended period of two weeks.

Molar-Mass Characterization of Cationic Polymers for Gene Delivery by Aqueous Size-Exclusion Chromatography

“…However, when the ionic strength of the eluent is too high, hydrophobic interactions will occur (24,27). Hydrophobic interactions can be minimized by addition of an organic solvent to the eluent (28). Our group has extensively investigated the water-soluble cationic polymer PDE and its copolymers and analogues in gene delivery systems (6,13,14,29Y32).…”

Precisely Designed Gold Nanoparticles by Surface Polymerization – Artificial Molecules as Building Blocks for Novel Materials

“…In pure DMF, most 4‐vinylthiophenol‐stabilized gold nanoparticles elute in the excess volume due to micelle formation or elute over the whole elution volume due to polar retention, even at low concentrations. This problem has been solved here by addition of LiBr (5 g L −1 ) to the eluent 11. In this case, the measurements were reproducible and two signals were detected.…”

Synthesis and characterization of synthetic polymer colloids colloidally stabilized by cationized starch oligomers

“…Enzymatic hydrolysis has been studied in the literature by chromatographic techniques, mainly SEC. However, we do not believe that the SEC separation of cationized starch can currently be quantitatively understood using literature data and methods, since the presence of both composition gradients and the branches means that separation is by size, not by molecular weight, and the presence of charges can lead to adsorption/aggregation effects, which currently plague SEC of polyelectrolytes 47, 48. Secondly, no standard is available for cationic starch to calibrate the columns.…”