Martin Held (Geesthacht / DE), Evgeni Sperling (Geesthacht / DE), Prokopios Georgopanos (Geesthacht / DE), Katharina Nieswandt (Geesthacht / DE), Volker Abetz (Geesthacht / DE)
Abstract text (incl. figure legends and references)
Tuning the morphology of block copolymer structures is an essential task in the development of polymer membranes.1 This is even more important when thermoresponsive block such as the poly((dimethyl acrylamide)-co-(isopropyl acrylamide)) as a copolymer with polystyrene (P(DMA-co-NIPAM)-b-PS) is involved. Such membranes are formed via a non-equilibrium self-assembly process in solution. In order to observe all the steps of the process in detail, from the synthesis to the membrane fabrication, a bundle of microscopic methods are necessary to be employed.
From the formation of micelles during emulsion polymerization, via the morphology in the polymer bulk to the membrane"s pore structure, microscopy is required to complement and confirm integral analysis methods. Starting from the polymer fabrication,cryoTEM was employed to observe micelles in the emulsion reversible addition fragmentation chain transfer (RAFT) synthesis of the block copolymer, a precursor for structure formation during the solidification of the membrane.2 Following that, TEM and AFM shed light onto the P(DMA-co-NIPAM)-b-PS bulk morphology as a first indicator for the final membrane structure. SEM investigations enable us to judge the quality of the final membrane. The images confirm the dynamic light scattering results regarding size and thermoresponsiveness, while also identifying the fabrication parameters for the final membrane. The structure of these thermoresponsive membranes would not have been identified without electron microscopic and atomic force microscopic imaging throughout their development.
1Müller and Abetz. Chemical Reviews 121 (22), 2021, p. 14189. DOI: 10.1021/acs.chemrev.1c00029
2Nieswandt et al. Polymers 14 (1), 2022, p. 62. DOI: 10.3390/polym14010062