How Rigid Are Anthranilamide\nMolecular Electrets?

As important as molecular\nelectrets are for electronic materials\nand devices, conformational fluctuations strongly impact their macrodipoles\nand intrinsic properties. Herein, we employ molecular dynamics (MD)\nsimulations with the polarizable charge equilibrium (PQEq) method\nto investigate the persistence length (<i>L</i><sub><i>P</i></sub>) of molecular electrets composed of anthranilamide\n(Aa) residues. The PQEq-MD dissipates the accepted static notions\nabout Aa macromolecules, and <i>L</i><sub><i>P</i></sub> represents the shortest Aa rigid segments. The classical model\nwith a single <i>L</i><sub><i>P</i></sub> value\ndoes not describe these oligomers. Introducing multiple <i>L</i><sub><i>P</i></sub> values for the same macromolecule follows\nthe observed trends and discerns the enhanced rigidity in their middle\nsections from the reduced stiffness at their terminal regions. Furthermore, <i>L</i><sub><i>P</i></sub> distinctly depends on solvent\npolarity. The Aa oligomers maintain extended conformations in nonpolar\nsolvents with <i>L</i><sub><i>P</i></sub> exceeding\n4 nm, while in polar media, increased conformational fluctuations\nreduce <i>L</i><sub><i>P</i></sub> to about 2\nnm. These characteristics set key guidelines about the utility of\nAa conjugates for charge-transfer systems within organic electronics\nand energy engineering.