On the afternoon of June 13th, Professor Kay Saalwächter from Martin Luther University of Halle-Wittenberg was invited to the Frontier Institute of Soft Materials to deliver an in-depth academic report on the structure and diffusion of homopolymer and copolymer gel networks. The lecture attracted many scholars and students from the field to discuss the latest research developments in polymer networks.

In his report, Professor Saalwächter first thoroughly explained the principles of time-domain proton double-quantum technology and its important application in characterizing the structure of polymer networks, such as quantitatively characterizing the cross-link density and defect content of polymer networks. Amphiphilic co-networks (ACNs), composed of cross-linked hydrophilic and hydrophobic macromolecular precursors, possess unique physical and chemical properties. A deep understanding of the structure and diffusion of such systems is especially important for the practical applications of these materials; Professor Saalwächter explored the structural characteristics of amphiphilic co-networks in selective and non-selective solvents in-depth, combining advanced characterization techniques such as small-angle X-ray scattering, NMR diffusion, and double-quantum magic-angle spinning NMR.

X-ray scattering experiments revealed the correlation lengths of the networks and the microphase separation (MPS) size characteristics in selective solvents, which are independent of concentration. By monitoring the diffusion coefficients of polysaccharides and polystyrenes with different molecular weights, the hydrodynamic screening length was estimated. Additionally, the local chain mobilities in the microphase-separated system were studied using DQ MAS NMR, showing immobilization of the linker end group and melt-like dynamics for clustered PCL chains, both of which qualitatively agree with bond-fluctuation Monte Carlo simulations of comparable model structures. This research not only enhanced understanding of the structural control of ACNs networks but also provided significant scientific basis for designing polymer materials with specific functions, such as drug delivery systems and tissue engineering scaffolds.

The lecture not only deepened the understanding of polymer networks among the attending scholars and students but also added valuable international perspective to the academic exchanges at South China University of Technology. Professor Kay Saalwächter's report sparked lively discussions, with attendees showing great interest in the advanced characterization techniques for polymer gel networks and the potential application prospects discussed in the report.