Conformational Selection of Polymer Chains upon π−π Interactions with Small Molecules

Conformational selection, pivotal in biological molecular recognition, remains underexplored in synthetic polymers, especially in the bulk states of polymers. This study reveals distinct conformational selection behavior in atactic polystyrene melts interacting with polycyclic aromatic hydrocarbons for the first time. Remarkably, despite structural similarities, anthracene and pyrene induce distinctly different conformations-trans and gauche, respectively. This divergence, attributed to the unique π-π interaction geometries, is captured by a "polymer cage" model, providing new insights into the precise structuring of polymers at the secondary structure level.