A thermosensitive supramolecular aggregation from linear telechelic polydimethylsiloxane with self-assembly units

A new thermosensitive material, polydimethylsiloxane supramolecular aggregation (PDMS-SMA-1), was prepared by coupling the N-pyridin-2-yl-succinamic acid with aminopropyl-terminated polydimethylsiloxane via amidated reaction. Its structure was confirmed by FT-IR, H-1 NMR and C-13 NMR. And the FT-IR spectra, molecular dynamics simulations and density functional theory calculations supported the existence of intermolecular hydrogen bonding and pi-pi stacking in supramolecular aggregation and obtained its possible self-assembly structure. A combination of DSC measurements, oscillatory shear experiments, and AFM measurements was carried out to further investigate the nature of PDMS-SMA-1. The results indicated that hydrogen bonding and pi-pi stacking combined with phase segregation were important for the preparation of thermosensitive materials. Moreover, in order to investigate the effect of molecular weight on the thermal sensitivity and morphology of supramolecular aggregation, PDMS-SMA-2 with higher molecular weight was also synthesized. In contrast to PDMS-SMA-1, it had similar thermal properties but different morphology. All the characteristics of supramolecular aggregation suggested a much wider range of hydrogen bonding and pi-pi stacking motifs which could be applied in intelligent materials.