Association Constant of the Charge‐Transfer Complex Between Pyrene and Naphthalenediimide Derivatives in PDMS Elastomers

Abstract Polydimethylsiloxane (PDMS) elastomers with varying crosslink densities were synthesized using prepolymers with different molecular weights. The association constants ( K a ) between a pyrene derivative (PySi) and naphthalenediimide derivative (NDISi) were measured in linear PDMS and PDMS elastomers. The shape of the absorption peak in the charge‐transfer (CT) band and the association constants were nearly independent of the crosslink density. Moreover, the temperature dependence of the association constants demonstrated consistent behavior across all PDMS media. This indicates that the structure of the CT complex and the Gibbs free energy of its formation in the PDMS are unaffected by the crosslink density, providing insights into the design of supramolecular architectures formed by the CT complex in a PDMS network.