Influence of Hydrogen Bonding on Rheological Behavior and DNA Sieving Performance of Acrylamide-Based Copolymer Solutions

Using N,N-dimethylacrylamide (DMA) and hydroxyethyl acrylamide (HEA) as comonomers, a series of P(DMA-co-HEA) copolymers with varying structural unit ratios were synthesized via solution polymerization. The hydrogen-bonding interactions in the polymer solutions and the effects of mass concentration, temperature, and shear rate on the rheological properties of the polymer solutions were systematically investigated. Concurrently, the copolymers were employed as sieving matrices in capillary electrophoresis applications to assess the impact of HEA content on the sieving performance of deoxyribonucleic acid (DNA) fragments. Rheological results revealed that, across different mass concentrations and temperatures, the thickening ability of P(DMA-co-HEA) reached its maximum at a structural unit molar ratio of n(DMA)/n(HEA) was 30, indicating that appropriate HEA structural units can improve the shear stability and high-temperature rheological stability of polymer solutions via hydrogen-bonding interactions. Furthermore, the evaluation of viscoelastic behavior demonstrated that a stable, weak hydrogen-bonded physical network is formed within the system when n(DMA)/n(HEA) ranges from 20 to 40. DNA fragment analysis further confirmed that the proper incorporation of HEA facilitates the enhancement of DNA sieving capability. Notably, when n(DMA)/n(HEA) was 30, the sieving matrix exhibited optimal separation performance, minimized peak attenuation, and excellent analytical reproducibility.