Synthesis And Characterization Of Novel Fluorinated Amphiphilic Copolymers And Their Applications

There are two parts in this thesis: (1) Synthesis and characterization of a seriesof amphiphilic hyperbranched star-block copolymers prepared viaoxyanion-initiated polymerization and their self-Assembly application; (2)Synthesis of amphiphilic fluorinated triblock copolymers and their application aspolymeric surfactant in miniemulsion polymerization of styrene.(1) Multicompartment Micelles from Hyperbranched Star-Block CopolymersContaining Polycations and Fluoropolymer SegmentIn this part, we have investigated the self-assembly of a series of amphiphilichyperbranched star-block copolymers to form multicompartment micelles in anacidic medium (pH 3.0) or in dimethylformamide/water (pH 3.0) mixture. Thesehyperbranched star-block copolymers were prepared via oxyanion-initiatedpolymerization process, using hydroxyl-terminated hyperbranchedpoly[3-ethyl-3-(hydroxymethyl)oxetane] (HP) as a macroinitiator precursor. It wasturned into oxyanion end-capped macroinitiator through the reaction withpotassium hydride, and followed by a sequential addition of 2-(N,N-dimethylamino)ethyl methacrylate (DMAEMA) and2,2,3,3,4,4,5,5-octafluoropentyl methacrylate (OFPMA). The resultantHP-star-PDMAEMA-b-POFPMA copolymers were characterized with ¹H NMRand ¹⁹F NMR and gel permeation chromatography (GPC). The analyses oftransmission electron microscopy (TEM), dynamic light scattering (DLS) andelectrophoresis confirmed that these copolymers could directly self-organized intosupramolecular multicompartment micelles with different diameters, depending onthe length of the PDMAEMA segment which can be protonated in acidic aqueousmedium. The measurement of the zeta potential gave further evidence of theaggregating structures for the multicompartment micelles.(2) Synthesis of Amphiphilic Fluorinated Triblock Copolymers and TheirApplication as Polymeric Surfactant in the Miniemulsion Polymerization ofStyrene Two kinds of amphiphilic fluorinated triblock copolymers comprisingmonomeric units of the macromonomer methyl methacrylate (MMA), 2-(N,N-dimethylamino) ethyl methacrylate (DMAEMA) and2,2,3,3,4,4,5,5-octafluoropentyl methacrylate(OFPMA) were synthesized viaoxyanion-initiated and characterized. These triblock copolymers were introducedto the miniemulsion polymerization of styrene as the polymeric surfactants. Toevaluate the effectiveness of these surfactants, the kinetics studies of theminiemulsion polymerization of styrene, which were carried out at the differentsurfactant amounts and pH values of the aqueous medium, were systematicallyconducted. The transmission electron microscopy (TEM), dynamic light scattering(DLS) and shelf life results indicated that the uniform polystyrene microsphereswere obtained on the optimal condition. As judged by aqueous electrophoresis andfourier transform infrred (FTIR), microsphere is composed of polystyrene core andPDMAEMA-b-POFPMA chains corona. This hairy particle structure was furtherconfirmed by the measurement of contact angles regarding to the films prepared bythe latex stabilized by the fluorinated triblock copolymer and analogousnonflurinated one, respectively.