The cooperativity of polycarbodiimides was probed at several length scales. Each experiment relies on formation of a predominance of a single-handed helix due to diastereomer formation. Polymerization of N-(R)-2,6-dimethylheptyl-$N\sp\prime$-hexyl carbodiimide, 1 ( ($\alpha$) $\sb{365}$ = +7.6, c = 1.67, 20$\sp\circ$C, chloroform), gives poly-1. Poly-1 adopts a kinetically controlled conformation during the polymerization ( ($\alpha$) $\sb{365}$ = 7.5, toluene, 20$\sp\circ$C); this polymer adopts a thermodynamic conformation upon annealing (65$\sp\circ$C, 24h ( ($\alpha$) $\sb{365}$ = $-$159, toluene, 20$\sp\circ$C)) or through the addition of benzoic acid (5 eq. acid per polymer repeat unit) at ambient temperature (ca. 1 h ( ($\alpha$) $\sb{365}$ = $-$144, chloroform, 20$\sp\circ$C)). The polymerization of 1 with its enantiomer (60% ee of 1) displays majority rules behavior; this polymer displays the same optical and conformational properties as a poly-1. The protonation of poly-1 with a chiral acid, camphorsulfonic acid (CSA), shows a diastereomeric interaction between the acid and the polymer. The (R)-CSA shows a more favorable interaction with poly-1 ( ($\alpha$) $\sb{365}$ = $-$300, chloroform, 20$\sp\circ$C) than the (S)-enantiomer ( ($\alpha$) $\sb{365}$ = 24, chloroform, 20$\sp\circ$C). Both acids protonate the polymer to the same extent as evidenced by similar pHs for the two samples (pH = $-$0.8 for both samples in THF). Polycarbodiimides are basic due to the presence of a guanidine-like repeat unit in the polymer backbone. Optically inactive poly(di-n-hexyl carbodiimide) was induced to adopt a predominance of one handedness through chiral protonation of the basic guanidine repeat units with (S)-CSA. At a ratio of 8:1 polymeric repeats:(S)-CSA a strong divergence from linearity occurred giving the polymer a specific rotation greater than 250$\sp\circ$ (365 nm, 20$\sp\circ$C, chloroform). Varying the amount of chiral anion present while holding the total acid concentration fixed demonstrates that the chiral anion concentration is independently responsible for the chiral induction.

A new synthetic route to C-2 bridged indenyl metallocenes utilizing the anion of 1-indanone has been developed. Two new ansa-zirconocene complexes, isopropylidene(cyclopentadienyl)(2-indenyl)ZfCl2 ( 1a) and isopropylidene (cyclopentadienyl)(2-(1-methyl-indenyl))ZrCl 2 (1b) were synthesized and examined as precursors for the polymerization of α-olefins. These metallocenes were shown to be active for the polymerization of ethylene and for the oligiomerization of propylene when activated with excess methylaluminoxane (MAO). A new route to isopropylidene bridged 2-indenyl metallocenes has been developed. Two new C-2 bridged ansa-zirconocenes, isopropylidene(1-indenyl)(2-indenyl)ZrCl 2 (10) and isopropylidene-bis(2-indenyl)ZrCl2 (11) have been synthesized and examined as pre-catalysts for the polymerization of ethylene and propylene. Both metallocenes were highly active for the polymerization of ethylene and the oligiomerzation of propylene when activated with excess methylaluminoxane (MAO) or [CPh3]+[B(C6F 5)4]−/Al(CH2CH(CH3) 2)3. The new pre-catalysts 10 and 11 were examined for the copolymerization of ethylene and styrene when activated with excess MAO. Both complexes 10 and 11 were highly productive for the copolymerization of ethylene and styrene with styrene incorporations of 29.2% and 21.0% by weight, respectively. 13C NMR studies indicated that there were no sequential or alternating styrene insertions in the copolymers, giving a unique polymer microstructure. X-ray diffraction studies indicated that the styrene units were excluded from the polymer lamella and that π-π interactions were taking place between the aromatic rings. The effect ansa-phenyl coordination in indenyl titanium half-sandwich complexes on α-olefin polymerization has been tested using indenyl titanium trichloride (19), 3-benzyl-indenyl titanium trichloride (20), and 3-benzhydryl-indenyl titanium trichloride (21). For styrene polymerization, the presence of pendant phenyl substituents decreases polymerization activity, decreases percent syndiotacticity, increases molecular weight, and decreases the observed melting point of the polymer. For ethylene polymerizations, the presence of pendant phenyl substituents decreases polymerization activity and generally increases molecular weight.

Eight new half-sandwich titanium catalyst precursors were prepared, and their catalysis of syndiospecific styrene polymerization when activated by methylaluminoxane was studied. Phenyl substitution increases polymerization activity in the order 15 $<$ 13 $<$ 11; the opposite trend was observed for the yield of syndiotactic polystyrene (s-PS). Benz (e) IndTiCl$\sb3$ (17) as well as the 2-methyl (19) and 1,2,3-trimethyl (23) derivatives were synthesized. Catalysts 17/MAO and 19/MAO exhibit exceedingly high activity, and produce s-PS with high stereoregularity and molecular weight. A variety of methoxy and phenyl-substituted (indenyl)titanium trichloride complexes were synthesized, and these precursors were used to polymerize styrene, ethylene, and propylene. The complexes, when activated with MAO, show only low activity for the polymerization of styrene and ethylene and no activity for propylene polymerization. Oxygen-aluminum coordination between the methoxy group and MAO could be one of the deactivating interactions. 9- ((2-t-Butylamino)ethyl) fluorene (66) was synthesized by the use of (1-chloro-2-t-butylamino)ethane (65) which provided convenient routes to 66 as well as 3- ((2-t-butylamino)ethyl) indene (67). Deprotonation of 66 with 2 equivalents of butyllithium followed by addition of ZrCl$\sb4$ or HfCl$\sb4$ led to (1-($\eta\sp1$-t-butylamido)-2-($\eta\sp5$-9-fluorenyl)ethane) zirconium (68) and hafnium (69) dichloride, respectively. Complexes 68 and 69 when activated with methylaluminoxane (MAO) are active catalysts for the polymerization of ethylene. A variety of new unbridged metallocene complexes were synthesized. Bis($\eta\sp5$-2-methylbenz (e) indenyl)zirconium dichloride (80) was activated with both MAO and triphenylcarbenium tetrakis(pentafluorophenyl)borate (trityl)/triisobutylaluminum (TIBA) producing polypropylene with varying molecular weight depending on polymerization temperature. The precursor ($\eta\sp5$-4,5,6,7-tetrahydro-1,2-dimethylbenz (e) indenyl)zirconium dichloride (101) when activated with trityl/TIBA produced a mixture of atactic and isotactic polypropylene (i-PP) with 51% mmmm pentads. The silicon bridged ansa-metallocene (dimethylsilanediylbis($\eta\sp5$-1,1$\sp \prime$-(4,5,6,7-tetrahydro-2-methylbenz (e) indenyl))) zirconium dichloride (105) was activated with MAO to produce i-PP with an activity of $1.0\times10\sp8$ g of PP/(mol of Zr$\rm\cdot\lbrack C\sb3H\sb6\rbrack{\cdot}h)$ and higher isotacticity than that produced by the unbridged analog (100). A new polycyclic ligand, 2-methylbenz (f) indene (111), was synthesized. Attempts to convert 111 into Group 4 organometallic complexes failed, however a rhodium dicarbonyl complex 112 was synthesized. The unsuccessful synthesis of Group 4 complexes was attributed to the loss of resonance stabilization in the proposed pentahapto coordinated complexes.

The objective of this research is to understand the relationship between polymers in bulk solution and at a surface. In particular, we are interested in studying, in situ, the adsorption of poly(dimethylsiloxane) (PDMS) from supercritical carbon dioxide (SC-CO2) onto a gold (Au) surface using Surface Plasmon Resonance (SPR) spectroscopy. By using a compressible supercritical fluid as the solvent, pressure variation becomes an important and simple way to “tune” the solvent quality and therefore vary the bulk free energy from good to nonsolvent behavior. These adsorption studies have potential for playing a role in some interesting industrial applications such as the prevention of reactor fouling and the coating of inner surfaces of porous media. Cloud point curves for liquid-liquid (L-L) phase separation for the PDMS/SC-CO 2 system were measured to provide a phase diagram over which to study the adsorption process. The cloud point curves for various PDMS samples in SC-CO2 were obtained as a function of pressure, temperature, and molecular weight using a variable-volume high pressure cell of our design. The system was observed to be thermodynamically stable in the one-phase region. As predicted by theory, the coexistence curves shifted to higher pressures as the difference in the molecular size of the two components (PDMS and SC-CO 2) increased. In addition, there were no strong concentration effects over the range studied (0.1–3wt% PDMS/SC-CO2). The adsorption behavior of PDMS from SC-CO2 was determined using the same high pressure cell with the SPR technique. The SPR method provided information about the optical and physical properties of the Au film, the adsorbed PDMS layer, and the bulk solution. This information was obtained by measuring the reflectivity as a function of incident angle for a glass/Au/Air, a glass/Au/SC-CO2, and a glass/Au/PDMS/PDMS-SC-CO2 solution system. The experimental values were then fitted using multi-layer methods and non-linear least squares fitting. From the experiments performed, it was noted that the thickness of the adsorbed PDMS layer could, in fact, be “tuned” by varying pressure. The results obtained demonstrate the adsorption of PDMS from SC-CO2 to a Au surface and indicate an increase in adsorption as phase separation is approached as well as complete wetting at the coexistence curve and within the two-phase region.

The control of surface properties, especially wetting behavior, is a major issue since many practical applications can be improved by tuning these behaviors. The ways in which topography and chemistry affect wettability have been studied extensively. Although, ultrahydrophobic and ultralyophobic surfaces have been prepared successfully by tailoring surface chemistry and topography, fabrication of stable hydrophilic surfaces has not received a lot of attention or has been complex and problematic. This work focuses on understanding how hydrophilicity is affected by surface chemistry and topography and generating ultrahydrophilic surfaces by utilizing functional polymeric and small molecules. Methyl-terminated reactive silane-containing methoxypoly(ethylene glycol)s (mPEGs) were synthesized and grafted on silica surfaces. Experimental and theoretical evidence reveals that the surfaces generated upon PEGylation possess significantly low hydrophilicity. These surfaces have lower values of contact angles only after hydration. We proved that contact angle values are significantly affected by the length scale of topography. Rough surfaces possessed much higher values of contact angles. In addition, vinyl and ester terminated monolayers were attached covalently on silica surface. Reaction kinetics and surface properties upon hydroxylation were also investigated. Vinyl terminated monolayers were dihydroxylated using osmium tetraoxide solution. Surfaces prepared by using trivinylcholorosilane produced lowest contact angles values after being dihydroxylated using osmium tetraoxide solution. However, the high wettability obtained for these groups diminishes over time due to surface reconstruction and contamination as evidenced from aging analysis. Ultrahydrophilic surfaces were prepared by adsorption casting of hydrolyzed poly(vinylene carbonate) (PVCa), poly(hydroxymethylene) (PHM), onto hydrophilic and hydrophobic surfaces. Aging analysis indicates that these surfaces resist loss of hydrophilicity. The study of adsorption temperature suggests that adsorption is faster at higher temperatures. Moreover, graft polymerization of vinylene carbonate (VCa) and vinyl ethylenecarbonate (VEC) were studied. Thin films of PVCa and PVEC were prepared by thermal and UV polymerization. Reduction of these films generated PHM and polyvinyl ethylene glycol) (PVEG) chains covalently attached to silica substrates.

Part I. The conductivities, electron spins, and g values of (MMn(DTO)$\sb2\rbrack\sb{\rm n}$ were determined where M = Cu(II), Ni(II), Pd(II), and Pt(II). The spin concentrations of each polymer are random comparing to the decrease of conductivities from (CuMn(DTO)$\sb2\rbrack\sb{\rm n}$ to (PtMn(DTO)$\sb2\rbrack\sb{\rm n}.$ Whereas the interchain distances increase from (CuMn(DTO)$\sb2\rbrack\sb{\rm n}$ to (PtMn(DTO)$\sb2\rbrack\sb{\rm n}$ due to the increase of atomic radii of M metals resulted in the increase of conductivities. It is concluded that the conductivities of (MMn(DTO)$\sb2\rbrack\sb{\rm n}$ polymers are greater along the interchain stacking than along the main chain. Part II. Segmented polyurethanes were prepared by reacting of soft polyol with diisocyanate to form a prepolymer then chain extended with a short chain diol to form high polymer. Stoichiometry considerations are critical for the synthesis of high molecular weight polyurethanes. Preliminary purification, drying, and molecualr weight determination of the starting materials and soft segments are extremely important. The segmented polyurethanes phase separated into hard and soft phases which was confirmed by the observation of constant glass transition temperature of each polymer system. None of the polymers showed reproducible melting transition due to the accompanied decomposition. p2BuDOP based polymers were the most acid-sensitive polymers in all five systems we studied. pAMMO/MDI/pDTM triblock copolymers with 16%, 26%, and 42% hard segment content are excellent elastomers. They showed reproducible melting transitions at maxima of $\sim$110$\sp\circ$C. The constant glass transition of each polymer indicates the polymers are phase-separated. They also showed acid-sensitivity because of the acetal structure. Rheological study showed the polymers melt at range from 50$\sp\circ$ to 120$\sp\circ$C.

Polymer production by P. oleovorans grown with various carbon substrates was investigated. Under the experimental conditions employed in this study, no limitation of nutrient was necessary to induce for this microorganism to produce polymers, but limiting nitrogen improved the polymer yield. The main repeating unit in polymers produced from n-alkanoic acids longer than heptanoic acid was either 3-hydroxyoctanoate or 3-hydroxynonanoate. Carbon sources examined for growth and PHA production were classified according to growth results. Both physical and chemical properties of the carbon substrate affected cell growth and PHA production. When a substituent was present, the better growth and PHA production were, the longer the separation between the carboxylic acid and the substituent was. Polymers containing various unusual groups such as olefin, nitrile, ester, bromine, alcohol, cyclohexane, and phenyl group were obtained by growing P. oleovorans wither either single carbon substrate or mixtures of two carbon substrates. Ninety-nine percent of repeating units in a PHA prepared from cells grown solely with 10-undecenoic acid, UND:, contained olefin group. PHAs produced from mixtures of two carbon substrates both of which support cell growth and PHA production were generally random copolymers with the exception of the polymer produced from mixtures of 5-phenylvaleric acid and either n-nonanoic acid, NA, or n-octanoic acid, OA. Many carbon substrates that support cell growth without PHA production were incorporated into the polymer when these substrates were co-fed to P. oleovorans with NA or OA. Polymers containing repeating units with bromine group could be prepared only when $\omega$-bromoalkanoic acids were fed in the presence of NA, but a polymer containing nitrile group were obtained when 11-cyanoundecanoic acid was fed in the presence of either NA or OA. PHAs containing unsaturated units were crosslinked by heating in the air or by heating with peroxides under nitrogen atmosphere to get rubber elastic products. Epoxidation of these polymers was also partially investigated.

Although supramolecular chemistry is a crucial participant in the formation and ordering of biomacromolecules, it is only recently that it has been utilized in the field of polymer chemistry. Polymers employing non-covalent interactions are becoming important in order to form dynamic and reversible macromolecular systems. To demonstrate the strength and versatility of supramolecular applications in synthetic macromolecules, we grafted recognition dyads as sidechain functionality upon the covalently held backbone. This approach enabled us both to tune material structure and properties and to construct higher order architectures. In our preliminary investigations, we studied a polystyrene-based system that self-assembled through aromatic stacking of electron-rich anthracene sidechains. We demonstrated that the complexation of this polymer with an electron-deficient guest resulted in an enhancement of thermostability to the globular polymer structure, dramatically altering the temperature dependence of polymer unfolding. We then employed azobenzene units as side-chain functionality to obtain a photochemical control over the polymer solution structure. We showed that photoisomerization of the azobenzene groups caused changes in sidechain-sidechain aromatic interactions, resulting in structural modulation of the polymer. Likewise, we grafted varying Donor-Acceptor-Donor hydrogen bonding sidechains to the polymer backbone to obtain more specificity in recognition. We demonstrated that intramolecular association between pendant groups resulted in folding of the polymer into a micelle-like structure in non-polar solvents. We also showed that the efficiency of recognition between the polymer and a complementary monomeric guest can be controlled through the choice of recognition element on the polymer by adjusting the balance between intra- and intermolecular interactions. We then extended the versatility of this “plug and play” strategy to bulk materials. Using spin casting, we kinetically trapped these host-guest complexes in polystyrene films, resulting in highly efficient recognition processes. Furthermore, we demonstrated the encapsulation of an electroactive guest into the intramolecularly hydrogen bonded polymer through NMR and electrochemical studies. Finally, we studied the intermolecular association of our polymers with other macromolecules. We demonstrated a polymer-mediated self-assembly of gold nanoparticles into highly ordered spherical arrays. We then extended this approach to the self-assembly of complementary polymer strands into giant vesicles through specific interchain hydrogen bonding.

Poly(trifluoroethylene) (PF3E) irreversibly adsorbs to oxidized silicon and covalently attached amine monolayers supported on silicon, producing hydrophobic thin films in the thickness range of 8-40 Å. The ultra-thin films of adsorbed PF3E were characterized here by means of contact angle, ellipsometry and X-ray photoelectron spectroscopy (XPS). Adsorption conditions such as reaction time, polymer concentration and solvent composition were also investigated. The adsorption behavior of PF3E can be explained by its ability to crystallize and form hydrogen bonds with proton acceptors, due to highly polar C-H bonds throughout the backbone. The hydrogen bonding - directed layer-by-layer assembly technique was used to build multilayers of poly(trifluoroethylene) (PF3E) and poly(4-vinylpyridine) (P4VP) from methanol solution. It was difficult to build up layers subsequent to the second layer, due to the replacement of an already formed layer by the adsorbing polymer. The remainder of this thesis describes the modification of metal oxide surfaces with organosilanes. Silicon-supported titanium oxide is modified by the reaction of hydridosilane (R3-nSiHn+1) in the vapor phase and in heptane solution at elevated temperatures. Surfaces are characterized by contact angle measurements and XPS. The preparation of hydrophobic alkylsiloxane layers on chromium surfaces by reaction of organosilanes R 3-nSiXn+1 (where X=Cl, OEt and H) was examined under two conditions: (1) in the vapor phase and (2) in toluene in the presence of ethyldiisopropylamine (EDIPA) using chloro- or ethoxysilanes, or in heptane using hydridosilanes. Surfaces were again characterized by contact angle analysis and XPS. Silicon-supported alkylsiloxane layers are prepared by the reaction of tri-n-hexylsilane and octylsilane in the vapor phase, in toluene and in ScCO2 at elevated temperatures, and octadecylsilane in the vapor phase and in toluene solution. It is shown that the layer structure depends on the reaction conditions. The kinetics of vapor phase reactions using tri-n-hexylsilane and octylsilane and ScCO2 phase reaction using octylsilane are described.

The "push-pull" electronically substituted polymers poly(2 (5) -bromo-5 (2) -n-hexyloxy-1,4-phenylene vinylene), poly(2 (5) -chloro-5 (2) -n-hexyloxy-1,4-phenylene vinylene) and poly(2 (5) -fluoro-5 (2) -n-hexyloxy-1,4-phenylene vinylene) were synthesized by a soluble precursor method and were used to fabricate light emitting diode (LED) devices. Thermal elimination of the polyether precursors gives final conjugated polymers as flexible red films. Precursor polymers can be spin-cast from solutions onto indium/tin oxide (ITO) pretreated quartz plates, then thermally converted to the final red polymers. Light emitting diode fabrication is then completed by the thin film vapor deposition of calcium, followed by aluminum. LED devices of the "push-pull" polymers give light emission in the 620-635 nm range. Two fluorinated polymers, poly(2-fluoro-1,4-phenylene vinylene) and poly(2,5-difluoro-1,4-phenylene vinylene) were investigated for their electroluminescent (EL) properties. LED's using these materials as emissive layers show substantial EL wavelength shifts (560 nm and 600 nm, respectively) relative to emission from unsubstituted poly(1,4-phenylene vinylene) (565 nm). These differences in EL emission can be attributed to the electronic effects of fluorine substitution. Synthetic strategies were developed for copolymeric materials based on poly(1,4-phenylene vinylene). The alternating block copolymer, poly (1,8-octanedioxy-2,6-dimethoxy-1,4-phenylene-1,2-ethenylene-1,4-phenylene-1,2-ethenylene-1,4-phenylene-1,2-ethenylene- 3,5-dimethoxy-1,4-phenylene) was synthesized by a modified Wittig polymerization utilizing trialkyl phosphonium salts. This resulted in a regiospecific trans-olefination reaction when compared to polymeric materials synthesized through the use of common triaryl-phosphonium salts. Harsh post-Wittig isomerization procedures using I$\sb2$ were bypassed as a result of the high trans-cis ratio of the final copolymer. It was fully characterized using the standard spectroscopic techniques as well as elemental analysis. Light-emitting single-layer diodes using the soluble, processible copolymer as the emitting layer gives green light with an electroluminescence maximum at 513 nm.