This thesis presents the first reported grafted PPE - polycaprolactone-g-PPE; the first PPE based sensing model: biotinylated grafted PPE/streptavidin coated sphere; the first photocrosslinkable PPE ¨C allyloxy PPE; and the new mechanism which demonstrates morphology control on a single molecular level

The road map of the semiconductor industry has followed Moores Law over the past few decades. According to Moores Law the number of transistors in an integrated circuit (IC) will double for a minimum component cost every two years. The features made in an IC are produced by photolithography. Industry is now producing devices at the 65 nm node, however, for every deceasing node size, both the materials and processes used are not only difficult but also expensive to develop. Ultimately, the feature size obtainable via photolithography is dependent on the wavelength used in the process. The limitations of photolithography will eventually make Moores Law unsustainable. Therefore, new methodologies of creating features in the semiconductor substrate are desired. Here we present a new way to make patterns in silicon (Si) and silicon dioxide (SiO2), molecular lithography. Individual molecules and polymers, in a monolayer, serves directly as the etch mask; eliminating the photolighographic size limitation of light at a specific wavelength. The Ohnishi- and Ring parameter suggests that cyclic carbon rich molecules have a high resistance towards the plasma process, used to create the features in the substrate. Therefore highly aromatic molecules were investigated as candidates for molecular lithography. A monolayer of poly cyclic hydrocarbons, fullerene containing polymer, and fullerene molecules were created using the versatile photochemistry of benzophenone as the linker between the substrate and the material. First, a chlorosilane benzophenone derivative was attached to the Si/SiO2 surface. A thin film of the desired material is then created on top of the silane benzophenone layer. Irradiation at ~350 nm excites the benzophenone and reacts with neighboring alkyl chains. After covalent attachment the non-bonded molecules are extracted from the surface using a Soxhlet apparatus. Self-assembly, molecular weight, and wetting properties of the material dictates the features shape and size. These features are then serving as an etchmask in a fluorine plasma. The organic etch resist is then removed either in an oxygen plasma or in a piranha solution. AFM analysis revealed that 3 to 4 nm wide defined structures were obtained using C96 as the etch mask. This is about ten times smaller then industry standards. Also a depth profile of 50 nm, which is the minimum feature depth used in industry, was created using a fullerene containing polymer as the etch mask. Directionality and control over the shape and sizes of the features are naturally critical for implementing this technology in device fabrication. Therefore, alignment of the materials used has also been examined. Monolayers of highly stable molecules has successfully been used as etch masks. Further research and development could implement molecular lithography in device fabrication. Self-assembly among other forces would dictate which materials could be used successfully as a molecular resist.

Nanotubes have numerous potential applications in areas such as biotechnology, electronics, photonics, catalysis and separations. There are several challenges to be overcome in order to realize their potential, such as: (1) Synthesis of monodisperse (in diameter and in length) single-walled nanotubes; (2) Quantitative understanding of the mechanism of formation and growth of nanotubes; (3) Capability to engineer the nanotube size; (4) Low temperature synthesis process; and (5) Synthesis of impurity free nanotubes. Our investigation focuses on a class of metal oxide (aluminosilicate/germanate) nanotubes, which are; single walled nanotubes with monodisperse inner and outer diameters, can be synthesized in the laboratory by a low temperature (95ºC) process in mildly acidic aqueous solutions, and their formation timescales is hours, which makes it convenient as a model system to study the mechanisms of nanotube formation. This work is focused on obtaining a qualitative and quantitative understanding of the mechanism of formation of aluminosilicate and aluminogermanate nanotubes. In order to achieve this overall objective, this thesis consists of the following aspects: (1) A systematic phenomenological study of the growth and structural properties of aluminosilicate and aluminogermanate nanotubes. The constant size and increasing nanotube concentration over the synthesis time strongly suggest that these nanotubular are assembled through self-assembly process. (II) Investigation of the mechanism of formation of single-walled aluminogermanate nanotubes provided the central phenomena underlying the formation of these nanostructures: (1) the generation (via pH control) of a precursor solution containing chemically bonded precursors, (2) the formation of amorphous nanoscale (~ 6 nm) condensates via temperature control, and (3) the self-assembly of short nanotubes from the amorphous nanoscale condensates. (III) Synthesis of mixed metal oxide (aluminosilicogermanate) nanotubes with precise control of elemental composition, diameter and length of the product nanotubes. (IV) Preliminary work towards generalization of the kinetic model developed for aluminogermanate nanotubes to a larger class of metal oxide nanotubes. It was found that the size of nanotubes is dependent on the amount of precursors that can be packed in a single ANP and in turn depends on the size of the ANP.

In this study, we investigate and fabricate two-dimensional ordered lattice structure by breath figures method. The breath figures pattern was prepared with the solution of carbon disulfide (CS2) doped with 1% weight concentration of polystyrene. The temperature and the humidity were controlled at ~23¢J and ~60 %, respectively. The breath figures pattern began to expand while CS2 is under evaporation. We explored the relationship between self-assemble of the water droplet and ordered structure via the solution height, the temperature evolution, and the dynamical optical images in the formation process of breath figures pattern. It was found that the radius of the water droplets varying with time follows the power law, £l ~ t £go; £g0=0.76. The fast Fourier transformation and Voronoi Diagram were used to conform that the formation of the breath figures pattern varied form a disordered state to an ordered state with the evaporation of CS2. The understanding of the breath figures pattern provides us to fabricate the photonics with size from nano- to micro-scale and to improve the application of nano device.

ABC type amphiphilic triblock copolymers, polyethylene-b-poly(ethylene oxide)-b-poly (£`-caprolactone) (PE-b-PEO-b-PCL), were synthesized through ring-opening polymerization. We have successfully synthesized hierarchical mesoporous silicas using a simple evaporation-induced self-assembly (EISA) strategy. Two blocks of hydrophobic segment (PE and PCL) in the triblock copolymer (PE-b-PEO-b-PCL) involved in two-type mesepores after calcinations. We recognized the PE segment attributed to face centered cubic (f. c. c.) morphology (spherical pore) and the PCL segment attributed to tetragonal cylinder structure (cylinder pore) by small angle X-ray scattering (SAXS), transmission electron microscopy (TEM) and specific surface area & pore size distribution analyzer (BET), respectively. We also investigated the effect on pore size and morphology with changing the molecular weight of PCL and the ratios of TEOS/template/HCl. We also synthesized the mesoporous phenolic resin by triblock copolymer poly(ethylene oxide)-b-poly(£`-caprolactone)-b-poly(L-lactide) (PEO-b-PCL-b-PLLA). After curing and calcinations, we also explored the morphology and pore size distribution of mesoporous phenolic by SAXS, TEM, BET. Because of the sequence of hydrophobic segment PCL and PLLA lay in the same side, so we could only observe hexagonal cylinder structure and one pore size.

In this article, a multiple-responsive polymer micelles system was constructed by using ionic bond to link the hydrophobic tetraphenylthiophene (TP) fluorophores, which possess the property of aggregation-induced emission enhancement (AIEE), with the hydrophilic poly(N-isopropyl acrylamide) (PNIPAM). The susceptibility of the ionic ammonium-sulfonate (Am-Sul) bonds towards metal ions, acid and base triggered the AIEE-operative fluorescence (FL) response. To exercise the idea, PNIPAM with sulfonate terminal was primarily prepared to react with TP-derivatives functionalized with ammonium groups to generate polymer complex of TP-PNIPAM. When in water, the polymer complex TP-PNIPAM formed micelles with the aggregated TP core interconnecting the hydrophilic PNIPAM shell by the ionic Am-Sul bonds. With the operative AIEE effect, the aggregated TP core of the micelles fluoresced but upon the additions of metal ions, acid and base, the ionic bonds dissociated to result in the collapse of the micelles and the FL quenching. A novel fluorogenic sensor capable to respond to multi-stimuli was therefore constructed. Amphiphilic micelle systems with the hydrophilic poly(N-isopropyl amide) (PNIPAM) shell and the hydrophobic tetraphenylthiophene (TP), which has the novel aggregation-induced emission enhancement (AIEE) feature, core inter-connected by ionic bonds were prepared in this study to explore the AIEE-operative emission response towards critical micelle concentration (CMC) and lower critical solution temperature (LCST). To exercise the idea, TP functionalized ammonium cations and PNIPAM with terminal sulfonate group were individually prepared and mixed together to yield three amphiphilic TP-PNIPAM complexes with different hydrophobic TP to the hydrophilic PNIPAM (x/y) ratios. When in aqueous solution, TP-PNIPAMs form micelles with the aggregated TP core, which emits strongly due to the operative AIEE effect, encompassed by the PNIPAM shell. The resultant CMC and LCST of the TP-PNIPAM micelles can be varied by changing the hydrophobic to the hydrophilic x/y ratio and can be monitored by the AIEE-dominant fluorescence responses towards concentration and temperature variables.

The objective of this research is to investigate three classes of block copolymers, the vesicle structures they form, their response to stimuli in solution and their capabilities for use in biomimicry. The self-assembled structures of all classes of polymers will be used as a basis for templating hydrogel materials, in the interior of the vesicles, and the resulting particles will be designed to show the structural and mechanical properties similar to living cells. The synthetic block copolymers are a poly(ethylene glycol) and poly(butadiene) (PEO-b-PBd) copolymer, a poly(ethylene glycol) and a poly(dimethyl siloxane) (PEO-b-PDMS) copolymer and the polypeptide block copolymer is a lysine and glycine (K-b-G) copolymer. Investigation using the synthetic block copolymers will focus on whether the polymer can form vesicles, size limitations of vesicle structures, and the formation of internal polymer networks. Subsequent investigations will look at the needed steps for biomimicry. The PDMS copolymer is a novel entrant into amphiphilic block copolymers. Although characterization of the copolymer solution behavior is known, the mechanical properties of the polymer are not known. PDMS was investigated along with the PBd polymer due to the similar chemical structure and nature. The lysine-glycine copolymers are a new system of materials that form fluid vesicle structures. Therefore, characterization of how K-b-G assembly behavior and investigations of how K-b-G responds to solution conditions are needed before incorporating this copolymer into a cellular mimic. The size and mechanical behavior of the lysine-glycine vesicles are measured to compare and contrast to the synthetic systems. The goals in creating a biomimic are a hollow sphere structure with a fluid bilayer, a vesicle that has controllable mechanical properties, and with a controllable surface chemistry and density. Overall, these experiments were successful; the various properties are easily controllable: the size of vesicles created, the material properties of the vesicle interior and shell, as well as the surface chemistry of the vesicles. Investigations into the novel block copolymers were conducted, and the polypeptide block copolymer showed the ability to create vesicles that are responsive to changing salt and pH concentrations. The PDMS block copolymer system offers a new material system that will perform as well as the PBd system, but without some of the inherent drawbacks.

None.

Self-assembly has big importance in synthesizing supramolecular structures. Highly fluorescent molecular squares with boradiazaindacene (BODIPY) building blocks were obtained via usage of metal driven self-asembly. The boradiazaindacene units were connected with the Pd(II) complex unit enforcing a near-90 degree angle between the building blocks. Thus, we believe we have the first example of BODIPY carrying fluorescent squares. With collective experience in BODIPY chemistry in our group, we may have the first example of functionalizable molecular square. Self-assembled light harvesting systems will be ultimate biomimetic example of photosynthetic reaction center.

We have designed and synthesized a fluorescent, self-assembled molecular square containing a highly fluorescent well known flurophore boradiazaindacene (BODIPY) dye. Pt(II) complexes were used to hold together BODIPY derivatives and give the right angle to form the square structure. Usage of BODIPY fluorophore is very important on such structures because its variety of superior properties. BODIPY is a well studied fluorophore in our group and it is known that this self assembled square can be easily modified to any area of use it is needed.