Exploration of new alkyne-based polymerization routes to functional polymers

Abstract

Polymerizations based on triple-bond building blocks have emerged as useful techniques for the construction of conjugated polymers with novel molecular structures and unique functional properties. In this thesis work, I have launched a program for developing alkyne-based polymerization methods from highly efficient small molecule reactions and exploring the properties and potential applications of the obtained polymer materials. Several acetylenic polymerization reactions have been successfully developed: (1) transition metal-free homocoupling polymerizations of bis(haloalkyne)s for the syntheses of 1,3-diyne-containing luminescent polymers and halogen-rich conjugated polyenyne, (2) palladium-catalyzed A₂+B₂ two-component polymerization of unactivated internal diynes and diphenols to generate polymers bearing heterocyclic benzofurans and (3) multicomponent polycouplings of terminal diynes, monoaldehydes and Lewis acids for the construction of stereoregular polymers with 1,5-dihalo-1,4-diene skeletons. The major research work of this program focused on the synthesis of diverse monomers, systematic study of polymerization behaviors, characterization of polymer structures and exploration of functional properties of the polymers and their practical applications. The acetylenic polymers were synthesized in high yields with high molecular weights (M_w up to ~1.7 × 10⁵). The structures and properties of the polymers were carefully characterized and evaluated by standard spectroscopic techniques such as IR, NMR, TGA, PL, XRD, XPS and elemental analysis. Apart from the excellent solubility and thermal stability, some novel functional properties, such as high light refractivity (refractive index up to ~2.1), aggregation-induced/enhanced emission and photosensitivity, were also discovered and demonstrated.

Date of Award	2016
Original language	English
Awarding Institution	The Hong Kong University of Science and Technology