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Design, synthesis, and characterization of functional block copolymers containing fluorinated or hydrophilic segments by ATRPBucholz, Tracy Laine, 1981- 04 September 2012 (has links)
Well-defined functional block copolymers containing either a fluorinated or a hydrophilic segment can be synthesized via a controlled free-radical technique, known as atom transfer radical polymerization (ATRP). Their self assembly characteristics in the solid state and in solution were examined in this work with the aim of developing ultralow dielectric constant materials and templates for conductive polymer synthesis, respectively. We demonstrated the controlled synthesis via ATRP of block copolymers containing poly(pentafluorostyrene) (PPFS) and a degradable polymer, such as poly(methyl methacrylate) (PMMA), poly([epsilon]-caprolactone) (PCL), or poly(D,L-lactide) (PLA). These block copolymers microphase separate in the solid state to form periodic nanostructures, such as alternating lamellae, a bicontinuous gyroid on a cubic lattice, cylinders on a hexagonal lattice, or spheres on a body-centered-cubic lattice, depending on the volume fraction of each block and the interblock segregation strength. Additionally, we quantified the interblock segregation strength of PPFS/PMMA, demonstrating that this block copolymer is only approximately twice as segregated as its nonfluorinated counterpart poly(styrene-[beta]-methyl methacrylate) due to the symmetric placement of the polar C-F bonds on the benzene ring in PPFS. We also showed that the self-assembly characteristics of PPFS-containing block copolymers can be used to create nanoporous fluorinated films with ultra-low dielectric constants in the range of 1.7 - 1.9. The dielectric constants are tunable through manipulation of the volume fraction of the degradable block in the parent block copolymers. We also demonstrated the controlled synthesis via ATRP of block copolymers containing poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAAMPSA) with either poly(oligo(ethylene glycol) methyl ether methacrylate) (PEGMA) or poly(methyl acrylate) (PMA). We showed that PEGMA/PAAMPSA formed well-ordered nanostructures in the solid state when cast from strong hydrogen bond accepting solvents, such as DMSO and DMF. PEGMA/PAAMPSA can also be used as the acid dopant in the synthesis of conductive polyaniline (PANI). Additionally, we studied the micelle formation of PMA/PAAMPSA and subsequently used these micelles as templates to create spherical conductive PANI nanoparticles. The size and size distribution of these PANI nanoparticles were dictated by the corresponding characteristics of the micellar template. / text
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Synthesis and characterizaton of novel polyester/polysiloxane and polyester/arylphosphine oxide copolymersKiefer, Laura A. 12 July 2007 (has links)
Novel, high molecular weight poly(dimethylsiloxane) / cycloaliphatic polyester segmented copolymers were prepared and characterized. Specifically, polyesters based on dimethyl 1,4-cyclohexane dicarboxylate and 1,4-butanediol were employed. The copolymers were synthesized via a melt process using a high trans content isomer which afforded semi-crystalline morphologies. Aminopropyl terminated poly(dimethylsiloxane) oligonlers of controlled molecular weight were synthesized and then end capped with excess diester to form a diester terminated amide linked oligomer. The latter was then incorporated into the copolymer via melt transesterification step reaction segmented copolymerization. The molecular weight of the polysiloxane and chemical composition of the copolymer were systematically varied to prepare a series of segmented polyester / poly(dimethylsiloxane) copolymers. / Ph. D.
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Synthesis and characterisation of amphiphilic block copolymersMorkel, Charl Ernst 03 1900 (has links)
Thesis (PhD (Chemistry and Polymer Science)--University of Stellenbosch, 2005. / This study involves the synthesis and characterisation of PEG-based amphiphilic block
copolymers for the hydrophilization of polysulphone ultrafiltration membranes. PEG
based macro RAFT agents were synthesized and characterised. PEG-b-PS block
copolymers were synthesized via the RAFT assisted controlled free radical polymerisation
utilizing the synthesized PEG macro RAFT agents. The resulting polymerisation products
were then analyzed by two-dimensional chromatography at the “critical conditions” for PS.
In the second phase of this study PEG-b-PSU block copolymers were synthesized via the
polycondensation of bis (4-chlorophenyl) sulphone, Bisphenol A, and PEG. The resulting
products were characterised by NMR spectrometry.
PEG-b-PS films and modified PSU membranes (modified by the addition of PEG-b-PSU
block copolymer to the membrane casting solution) were prepared and analyzed. Surface
analyses included static contact angle, AFM force-distance analysis, and FTIR-PAS
analysis.
Results showed the successful synthesis of both PEG-b-PS and PEG-b-PSU amphiphilic
block copolymers. Surface analysis proved the successful hydrophilization of the surface
of the modified PSU membranes.
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