Macromolecules, Vol.47, No.13, 4160-4168, 2014
Sequential "Click" Synthesis of "Nano-Diamond-Ring-like" Giant Surfactants Based on Functionalized Hydrophilic POSS/C-60 Tethered with Cyclic Polystyrenes
This paper reports the design and facile synthesis of a novel series of "nano-diamond-ring-like" giant surfactants composed of a functionalized hydrophilic polyhedral oligomeric silsesquioxane (such as dihydroxyl-functionalized DPOSS) or fullerene (such as carboxylic acid-functionalized AC(60)) head as the "diamond" and a hydrophobic, cyclic polystyrene (CPS) tail as the "ring". The synthetic route combines several steps of "click-type" reactions, demonstrating highly efficient and modular features. Starting from a specifically designed initiator, trifunctional linear polystyrene (LPS) precursors bearing vinyl, bromo, and alkyne groups were prepared by atom transfer radical polymerization (ATRP). Upon the subsequent azidation of LPS, copper-catalyzed Huisgen [3 + 2] cycloaddition reaction was employed to afford vinyl-functionalized CPS ring in high yield and purity. The vinyl group was then subjected to the thiol-ene reaction to introduce an azide group onto the CPS, providing an azide-functionalized CPS (CPS-N-3) as a "clickable" cyclic building block to construct giant molecules. Various "nano-diamond-ring-like" giant surfactants decorating with different "diamonds", such as hydrophilic DPOSS or AC(60) molecular nanoparticles, can be readily synthesized via the modular sequential "click" approaches based on this CPS-N-3 building block. These giant surfactants with structural precision represent a novel member in the MNP-based giant surfactant family which might have distinct self-assembly behaviors compared to their linear analogues.