Polymers under Multiple Constraints: Restricted and Controlled Molecular Order and Mobility

This virtual issue collects articles originating from the Collaborative Research Center/Transregio (CRC/Transregio) TRR 102 that was funded by Deutsche Forschungsgemeinschaft (German Foundation) 2011 to 2023. The CRC a joint activity between Martin Luther University Halle-Wittenberg and Leipzig University. Furthermore, projects several neighboring research institutions were included. Its title, “Polymers under multiple constraints: Restricted controlled molecular order mobility”, reflects fact in macromolecular systems formation of structural on monomer scale is complex process as it constrained its environment due connectivity polymer chain. In such processes structure self-assembly investigated, which structures dynamics are affected chain additional constraints specific interactions, external forces, geometrical confinement, crowding, or topological restrictions. Two outstanding examples ordering central topics crystallization field synthetic polymers amyloids proteins. comparison these two fields targeted has finally led new studies hybrid containing elements representative both biological macromolecules during last funding period. Polymer well-established field, yet consensus crucial aspects not been achieved, particularly regarding mechanisms leading semicrystalline morphologies ultimately determine mechanical properties. Moreover, given results hierarchical spanning across length scales, obvious mentioned above play significant role. Until today, comprehensive understanding processing conditions intricate relationship microscopic properties remains limited. It hoped more fundamental this can contribute knowledge-based transition today's commodity modified designs amenable recycling be produced sustainable way. Amyloids fibrils, linear protein aggregates, known associated with neurodegenerative disorders but also exist functional aggregates. They consist (mis)folded proteins share partial local scale, nucleation growth larger ordering, appearance universal features polymers. Physicochemical predominantly focuses deciphering underlying aggregation, studying intermediate states, interplay aggregate morphology, kinetic processes. Although CRC's area directly aimed at medical impact, knowledge will provide helpful background for addresses pharmacological issues (Figure 1). following brief overview issue, comprises number articles, perspectives reviews, published recently Macromolecular Chemistry Physics, Bioscience, Theory Simulations report obtained within attempt place broader context related research. review Kay Saalwächter co-workers (macp.202200424) gives an recent developments concerned elucidating bulk melts, focus factors have received less systematic attention before. Effects presence absence motion through crystallites entanglements morphology specifically addressed CRC. On theoretical side effort made analyze driving forces equilibrium simulations using advanced methods Monte Carlo simulations. Analysis thermodynamics single transitions allowed work out similarities differences folding. article Saalwächter, Thomas Thurn-Albrecht, (macp.202200459) shows polybutylene succinate lacks intracrystalline exhibits typical morphological previously found model case. Mario Beiner (macp.202200433), series high performance aliphatic polyamides longer methylene sequences examined, focusing existence different polymorphs effects flow. subsequent papers nucleation, crystal initiated. Wycliffe Kiprop Kipnusu co-workers, macp.202200443, use combination experimental techniques, namely fast scanning calorimetry (FSC) Fourier transform infrared (FTIR) spectroscopy follow evolution calorimetric interactions homogeneous quenched amorphous polyethylene terephthalate (PET). While homogenous typically prevails large supercooling, commonly induced interfaces higher temperatures, usually subsumed term heterogeneous nucleation. perspective “On Thermodynamics Kinetics Interface-Induced Crystallization Polymers” Oleksandr Dolynchuk Thurn-Albrecht (macp.202200455) summarizes alternative prefreezing. direct observation description latter achieved CRC, explored establishing basis analysis initial stages interface-induced crystallization. Jörg Kressler (macp.202200428) deals special case 2D surface water. Here influence tacticity poly(methacrylic acid) investigated. Tress co–workers (macp.202200452), 3D confinement small droplets studied approach nanostructured electrodes dielectric spectroscopy. development simulation methods. An example documented Stefan Schnabel Wolfhard Janke titled “Monte Simulation Long Hard-Sphere Chains Five Dimensions”, very efficient off-lattice method applied classical problem physics (mats.202200080). Christian Lauer Wolfgang Paul, mats.202200075, coarse-grained study folding aggregation polyglutamin, supposed important role Huntington's disease, hereditary disease. Atomistic comparing force used understand incorporation n-alkanes into phospholipid bilayers Anika Wurl Tiago M. Ferreira (mats.202200078). “Thermoplasmonic Manipulation Study Single Polymers Protein Aggregates” Frank Cichos method-oriented reviews fundamentals applications thermoplasmonic manipulation emphasis trapping peptide aggregates (macp.202300060). concludes variety hydrodynamic advantageously alongside thermo-osmosis yield thermofluidics. Based extended NMR experiments complemented other methods, Benedikt Schwarze Daniel Huster (mabi.202200489) give how mutations sites amyloid