The Effect of Intramolecular Cross‐Linking on Polymer Interactions in Solution

• Published in: Macromolecular rapid communications. Vol. 39; no. 16; pp. e1800407 - n/a
• Main Authors: Galant, Or, Davidovich‐Pinhas, Maya, Diesendruck, Charles E.
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.08.2018
• Subjects: Addition polymerization; Biological materials; Chain mobility; critical concentration; entanglements; intramolecular collapse; Macromolecules; Mimicry; Organic chemistry; Particle interactions; Polymers; Proteins; Rheological properties; Rheology; solvent quality; solvent quality; intramolecular collapse; critical concentration; rheology; entanglements
• ISSN: 1022-1336; 1521-3927
• DOI: 10.1002/marc.201800407

The conformation of a polymer in a solvent is typically defined by the solvent quality, which is a consequence of the solvent and macromolecule's chemistry. Yet, additional factors can affect the polymer conformation, such as non‐covalent interactions to surfaces or other macromolecules, affecting the amount of polymer–solvent interactions. Herein, chemically folded polymers with protein‐like architectures are studied and compared to their unfolded linear precursor in good solvents using rheology measurements. The current research reveals that permanent folding by intramolecular chemical cross‐linking limits the chain mobility and therefore causes a reduction in polymer–solvent interactions, making a good solvent become theta. This change not only affects the “solvent quality” but also leads to a change in particle–particle interactions as a function of concentration. These findings provide crucial insight into the effects of intramolecular cross‐links on macromolecule solubility and self‐assembly, which are critical for mimicking structurally similar biological materials. Keeping the solvent out! The effect of intramolecular collapse on the polymer–polymer–solvent interactions is presented and new findings reveal that the interaction of a “good” solvent for linear polymer architecture becomes “theta” when the chain presents high internal cross‐link density. In addition, the critical concentration in which interactions between chains occur differs; however, the critical concentration for entanglement remains unchanged.