SYNTHESIS AND CHARACTERIZATION OF MONOMERS AND POLYMERS CONTAINING MULTIPLE P-ARYLENEAZO OR P-BENZOQUINODIIMINE GROUPS: CONDUCTING POLYMERS, LIQUID CRYSTAL POLYMERS, AND DIPOLAR POLYMERS.
KeywordsAniline black -- Electric properties.
Polymer liquid crystals -- Electric properties.
Polymers -- Electric properties.
AdvisorHall, H. K.
MetadataShow full item record
PublisherThe University of Arizona.
RightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
AbstractAniline Black, a polymer containing p-benzoquinodiimine groups, was synthesized chemically or electrochemically by the oxidation of aniline. The polymer salts showed the conductivity of 10⁻¹-10⁻³ ohm⁻¹cm⁻¹. Polymers containing anthroquinodiimine units were also prepared by polycondensations. The syntheses of model compounds containing p-benzoquinodiimine were attempted. Multiazobisphenol monomers were synthesized. 4,4'-(3,3'-Dimethyl-4,4'-biphenylenebisazo) bisphenol 7, 4,4'-[azobis(p-phenyleneazo)] bisphenol 8, and 4,4'-(2-methoxy-1,4-phenylenebisazo) bisphenol 10 displayed liquid crystal (l.c.) properties, while model derivatives of 7, 8, and 4,4'-(4,4'-stilbenebisazo) bisphenol 9 did likewise. Monomers and derivatives of 4-[(4-hydroxyphenyl)azo]-1-naphthol 5, and 4,4'- [oxybis(p-phenyleneazo)] bisphenol 6 showed no l.c. behavior. New thermotropic polyesters based on these multiazobisphenols were synthesized. Sebacates of 5, 6, 7, 8, and 10 showed l.c. behavior, while polymers based on isophthalic or 5-t-butylisophthalic acid did not do so. Polyformals were also synthesized from these momoners, only that of 4 showed weak l.c. behavior. The correlation between the structure of these polymers and their tractabilities, electrical properties, liquid crystal behaviors was studied. Polymers and copolymers containing p-azoarylene and p-azoxyarylene groups were synthesized by oxidative coupling of various aromatic diamines. Films were cast directly from the reaction mixtures or from the polymer solution. The films were n-doped by sodium naphthalide or p-doped by iodine. They showed electrical conductivities of 10⁻⁴ to 10⁻⁵ ohm⁻¹cm⁻¹. AB monomers containing dipolar p-phenyleneazo groups were synthesized: 4-(4-hydroxy-2-methoxyphenylazo) benzoic acid 21, 4-[4-(4-hydroxy-2-methoxyphenylazo)-2-methoxyphenylazo] benzoic acid 22, and 4-(4-hydroxy-2-methoxyphenylazo)-3-nitrobenzoic acid 23. The monomers were polymerized by direct polycondensations. The polyester synthesized from 21 formed a red, transparent film. A polymethacrylate containing dipolar p-phenyleneazo groups in the side chains was also prepared by the free radical polymerization of 1- [3-methoxy-4-(p-nitrophenylazo)-phenoxy] hexyl methacrylate 28.
Degree GrantorUniversity of Arizona
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I. Tunable Luminescence in Dendronized Poly(phenyleneethynylene)s Through Post-Polymerization Chemical Modification II. Rigid, Helical Polymers Based Upon Chiral HydrobenzoinMcGrath, Dominic V.; Sisk, David Theodore; McGrath, Dominic V.; Mash, Eugene A.; Pyun, Jeffrey; Armstrong, Neal R.; Hall, H. K., Jr. (The University of Arizona., 2007)Dendritic encapsulation of poly(phenyleneethynylene)s or PPEs has been shown to enhance photoluminescent quantum efficiency and facilitate energy transfer by funneling photonic energy absorbed on the dendron periphery efficiently to the conjugated polymeric core. The research presented herein focuses on incorporating degradable dendron onto PPEs, examining whether or not similar benefits were conferred upon the proposed system and controlling polymer luminescence through the elimination of the insulating macromolecules. PPEs appended with disassembling dendrons of various generation sizes were synthesized and their optical properties studied. Polymer luminescence was then quenched via chemical degradation of the disassembling dendrons. Furthermore, the macromolecules resulting from disassembly exhibited tunable luminescence properties upon manipulation of pH. Consequently, it was determined that polymer luminescence could be controlled upon forming phenolic moieties along the PPE backbone. Tunable emission was later realized in the thin film as well through the integration of crosslinkable dendrons onto the polymer core.Recently, helical synthetic linear polymers have demonstrated the ability to facilitate stereoselective processes such as catalysis, recognition and separation. Consequently, it has become increasingly desirable to develop new platforms capable of imparting asymmetry. The work presented herein describes the synthesis of a series of polymers based upon chiral hydrobenzoin and the subsequent conformational analysis performed on these materials. It was envisioned that these polymeric materials might inherently possess conformational asymmetry and as result could be able to impart configurationally chirality by introducing a diastereomeric bias for the formation of one enantiomer over the other during the course of the reaction.
The synthesis of new electro-optic polymers.Hall, H. K.; Weinschenk, Joseph Iddings, III.; Mulvaney, J. E.; Padias, Anne; Green, David; Lee, Cherylyn (The University of Arizona., 1987)This work involves the synthesis of two types of electro-optic monomers and their corresponding polymers. The first type of monomers contain the p-oxy-α-cyanocinnamate structure and were synthesized from ω-hydroxyalkoxy-substituted benzaldehydes and methyl cyanoacetate. These ω-hydroxy-α-cyanoester monomers show a high degree of electron delocalization. Copolyesters were synthesized by copolymerization of these monomers with methyl 12-hydroxydodecanoate by the standard two-stage, high-temperature polyesterification procedure. The copolyesters, incorporating dipolar units all pointing in the same direction, are soluble and solution- and melt-processable. Second harmonic generation (SHG) measurements on chloroform solutions of the copolymers showed enhancements of χ² as large as 20 relative to the dipolar monomers. These are the first known readily soluble main chain polymers that exhibit SHG behavior. The second type of monomers were acrylates containing substituted phenyl esters of benzoic acid as mesogenic (pendant) groups. Specifically, the mesogenic group contained an oxy-aryl-carboxy-aryl-carboxy-alkyl structure separated from the acrylate carbon-carbon double bond by a spacer group, which had a carboxyethyl-carboxyhexyl structure. A synthetic route was established by synthesizing a model monomer containing a 2-methylpropyl group as the alkyl group at the end of the mesogenic group. The model monomer was polymerized free radically and the resulting polymer found to possess a smectic liquid crystalline phase that became isotropic at 103° C. With the synthetic route established, an optically active monomer containing a (S)-2-methyl-1-butyl group as the alkyl group at the end of the mesogenic group was synthesized and polymerized. The optically active polymer was already in a smectic liquid crystalline phase at room temperature (≈25° C) and the phase persisted up to 72.6° C. These results indicate that it is possible to design polymers containing thermotropic liquid crystalline phases by fixing low molecular weight liquid crystalline molecules to a polymer main chain.
Dithiafulvene (1,3-dithiole) and acrylate liquid crystals: Synthesis of monomers and polymers with possible electronic and electro-optic applications, and investigations in the synthesis of pure (meth)acrylates.Hall, H. K.; Evans, Stacy Alexandria Banford. (The University of Arizona., 1989)In this work, using the idea of an electrically conducting "functional unit," monomers and polymers with possible electronic and electro-optic applications were synthesized. The synthesis and polymerizations were, in many cases, novel and non-trivial. Dithiafulvene (1,3-dithiole) and variations of this functional unit were synthesized and incorporated into new condensation polymers. Polyesters, polyamides and polyhydrazones were all successfully synthesized and could be cast into films. These new polymers might be applicable as processable conducting materials if compatible dopants are employed or by themselves in the area of third order non-linear optics. Using a (meth)acrylate backbone, a spacer group of six methylene units, and a phenyl-CO₂-phenyl mesogen, linked by an ester group to a strongly polar optically active center containing a methoxy group, three new novel monomers and polymers were designed to exhibit smectic C* liquid-crystal phases. The polymers exhibited liquid crystalline behavior as was shown in differential scanning calorimetry and optical microscopy. Further studies and investigations in the synthesis of pure (meth)acrylate esters and their homopolymers yielded surprising results with regard to the Schotten-Baumann reaction. Interestingly, the use of meth(acryloyl) chloride in this scheme leads to (meth)acrylic anhydride, which is not easily isolable from distillable products. This anhydride is responsible for gelation in the polymerization of glycolate esters, and cannot be removed by work-up with various nucleophiles without disrupting desired ester functions. An S(N)2 method is recommended in this work.