The emerging field of nanotechnology, which spans diverse areas such as nanoelectronics, medicine, chemical and pharmaceutical industries, biotechnology and computation, focuses on the development of devices whose improved performance is based on the utilization of self-assembled nanoscale components exhibiting unique properties owing to their miniaturized dimensions. The first phase in the conception of such multifunctional devices based on integrated technologies requires the study of basic principles behind the functional mechanism of nanoscale components, which could originate from individual nanoobjects or result as a collective behaviour of miniaturized unit structures. The comprehensive studies presented in this thesis encompass the mechanical, dynamical and photophysical aspects of three nanoscale systems. A newly developed europium sulfide nanocrystalline material is introduced. Advances in synthetic methods allowed for shape control of surface-functionalized EuS nanocrystals and the fabrication of multifunctional EuS-CdSe hybrid particles, whose unique structural and optical properties hold promise as useful attributes of integrated materials in developing technologies. A comprehensive study based on a new class of multifunctional nanomaterials, derived from the basic unit of barcoded metal nanorods is presented. Their chemical composition affords them the ability to undergo autonomous motion in the presence of a suitable fuel. The nature of their chemically powered self-propulsion locomotion was investigated, and plausible mechanisms for various motility modes were presented. Furthermore functionalization of striped metallic nanorods has been realized through the incorporation of chemically controlled flexible hinges displaying bendable properties. The structural aspect of the light harvesting machinery of a photosynthetic cryptophyte alga, Rhodomonas CS24, and the mobility of the antenna protein, PE545, in vivo were investigated. Information obtained through a combination of steady-state and time-resolved spectroscopy in conjunction with quantum chemical calculations aided in the elucidation of the dynamics and the mechanism of light harvesting in the multichromophoric phycobiliprotein phycocyanin PC645 in vitro. Investigation of the light-harvesting efficiency and optimization of energy transfer with respect to the structural organization of light-harvesting chromophores on the nanoscale, can provide us with fundamental information necessary for the development of synthetic light-harvesting devices capable of mimicking the efficiency of the natural system.

This work presents a novel means of producing thin-film light-emitting devices, functioning according to the principle of electroluminescence, using an inkjet printing technique. This study represents the first report of a light-emitting device deposited completely by inkjet printing. An electroluminescent species, doped zinc sulfide, was incorporated into a polymeric matrix and deposited by piezoelectric inkjet printing. The layer was printed over other printed layers including electrodes composed of the conductive polymer poly(3,4-ethylenedioxythiophene), doped with poly(styrenesulfonate) (PEDOT:PSS) and single-walled carbon nanotubes, and in certain device structures, an insulating species, barium titanate, in an insulating polymer binder. The materials used were all suitable for deposition and curing at low to moderate (<150°C) temperatures and atmospheric pressure, allowing for the use of polymers or paper as supportive substrates for the devices, and greatly facilitating the fabrication process. The deposition of a completely inkjet-printed light-emitting device has hitherto been unreported. When ZnS has been used as the emitter, solution-processed layers have been prepared by spin-coating, and never by inkjet printing. Furthermore, the utilization of the low-temperature-processed PEDOT:PSS/nanotube composite for both electrodes has not yet been reported. Device performance was compromised compared to conventionally prepared devices. This was partially due to the relatively high roughness of the printed films. It was also caused by energy level misalignment due to quantization (bandgap widening) of the small (<10 nm) nanoparticles, and the use of high work function cathode materials (Al and PEDOT:PSS). Regardless of their reduced performance, inkjet printing as a deposition technique for these devices presents unique advantages, the most notable of which are rapidity of fabrication and patterning, substrate flexibility, avoidance of material wastage by using drop-on-demand technology, and the need for only one main unit operation to produce an entire device.

This thesis focuses on the generation of fine cell polymer foams using a heterogeneous nucleating agent (nanoclay), appropriate polymer blending strategies and accurate control of foam processing parameters. Foaming behaviour of HMSPP/ clay nanocomposites and HMS-PP/EVA/clay nanocomposite blends is studied using a batch and a continuous foam injection moulding system. Morphological studies using TEM and SEM led to a few interesting deductions. It is very difficult to attain complete exfoliation in case of HMS-PP/clay nanocomposites even at low clay loadings due to a non polar nature and low graft efficiencies of HMS-PP matrix. The addition of clay to an immiscible blend of HMS-PP/EVA results in compatibilization between the dispersed and the continuous phase. Nanocellular foams (290 nm) were subsequently generated in the batch process at a foaming temperature of 147oC and 25 seconds foaming time. The addition of immiscible EVA-28 to the HMS-PP matrix in presence of clay particles further results in reduction of foam cell sizes to 100 nm. The effect of gas concentration, foaming temperature, injection pressure, and foaming time on foam cell size was studied. It was found that the foam cell size was highly sensitive to the injection pressure at the mould gate (hence pressure drop rate) and foaming temperature. The cell size linearly decreased with increase in gas concentration and foaming time. The sensitivity of foam cell sizes to changes in processing parameters decreases with increase in clay concentration. The effect of addition of clay particle on gas solubility was modelled using the Guggenheims contact fraction approach and subsequently a new model to predict gas solubility was developed using statistical thermodynamic tools. Additionally the effect of shear and extensional rheology on foam cell morphology was modelled. It was found that the viscoelasticity of the polymer matrix greatly affects cell sizes as compared to extensional viscosity.

The emergence of unique or enhanced physical, chemical and optical material properties at the nanoscale underlies the swift rise of nanomaterials science over recent decades. Within this interdisciplinary field, catalysis performed by nanomaterials (i.e. nanocatalysis) is one area where differences between nanoscale and bulk material properties offer particularly attractive opportunities for application. The consequent pursuit of viable nanomaterials with unprecedented catalytic activity has inevitably expanded across the periodic table, whereby a number of highly efficient precious metal, metal oxide and composite nanostructured catalysts have been developed for a wide range of synthetic organic and inorganic transformations. The lanthanide series has not been excluded from this search, but is still underrepresented in catalysis despite some rich chemistry and reactivity which sets these elements apart from many other metals. More recently however, the necessary paradigm shift away from commonly utilized but expensive, potentially toxic precious metal catalysts, and toward more sustainable alternatives, has seen an upsurge in the development of novel nanomaterials for heterogeneous catalysis: the general topic of this doctoral thesis. Heterogeneous nanocatalysis offers distinct advantages over homogeneous catalysis. Catalyst recyclability, ease of separation from reaction mixtures, and minimal product contamination all contribute to the higher overall effectiveness of heterogeneous catalysts relative to their homogeneous counterparts. The use of light as an abundant reagent, both in nanomaterial fabrication and for photocatalysis, is another attractive prospect. This dissertation addresses both points, describing the iterative development and application of photochemically-prepared samarium oxide based nanomaterials for heterogeneous catalysis and photocatalysis. Through a series of related peer-reviewed publications and associated commentary, the evolution of the application-driven design of a nanomaterial which is both efficient and effective for a diversity of heterogeneous catalytic and photocatalytic transformations is presented. Major findings include 1) both colloidal and supported samarium oxide nanoparticles can be prepared photochemically and comprise primarily Sm2O3 but may contain localized mixed valences or dynamic surface oxidation states; 2) colloidal samarium oxide nanoparticles possess high activity for Brønsted acid and oxidative catalysis, but recyclability and overall effectiveness is less than optimal due to a combination of polydispersity and size-dependent catalytic activity; 3) a similarly-prepared “second generation” samarium oxide/titanium dioxide nanocomposite presented several advantages over its predecessor, performing highly efficient and effective pure heterogeneous, dual photoredox-Lewis acid catalysis in two different types of synthetically relevant photocyclizations. Effects of different nanoparticle supports, rare insights into the catalytic mechanisms and behaviour of these nanomaterials‒obtained at the single molecule level by innovative application of Total Internal Reflection Fluorescence Microscopy (TIRFM) to catalysis research‒as well as advances in TIRFM data analysis protocols, are also discussed.

55 f. / Submitted by Ana Hilda Fonseca (anahilda@ufba.br) on 2013-10-02T13:52:06Z No. of bitstreams: 1 Dissertação_Impressão FINAL.pdf: 23959288 bytes, checksum: 4ba5e564089149b8fafe9a4c74558367 (MD5) / Approved for entry into archive by Ana Hilda Fonseca(anahilda@ufba.br) on 2013-10-02T14:12:03Z (GMT) No. of bitstreams: 1 Dissertação_Impressão FINAL.pdf: 23959288 bytes, checksum: 4ba5e564089149b8fafe9a4c74558367 (MD5) / Made available in DSpace on 2013-10-02T14:12:03Z (GMT). No. of bitstreams: 1 Dissertação_Impressão FINAL.pdf: 23959288 bytes, checksum: 4ba5e564089149b8fafe9a4c74558367 (MD5) Previous issue date: 2013 / O sulfeto de bismuto faz parte da família de compostos do tipo A2VB3VI formados por calcogênios e metais (sendo A= Sb, Bi. B= S, Se, Te) que se destacam por suas propriedades semicondutoras. O Bi2S3 forma um sólido de coloração preta de solubilidade muito baixa em água, possuindo energia de band gap na faixa de 1,3 a 1,7 eV, com potencial para aplicações nas áreas de optoeletrônica e fotocatálise, entre outras. As propriedades físicas e químicas de nanopartículas de Bi2S3, e outros nanomateriais, são fortemente dependentes de diferentes tamanhos e morfologias dos nancristais. Este trabalho teve como objetivo desenvolver um método sonoquímico para produção de nanopartículas de Bi2S3. Utilizou-se os reagentes Bi(NO3)3 e Na2S2O3 como precursores dissolvidos em solvente orgânico contendo o surfactante brometo de cetiltrimetilamônio (CTAB), sendo o meio reacional exposto a irradiação de ultrassom de alta intensidade, através de um sistema com sonda de titânio e imersão direta. As nanopartículas de Bi2S3 obtidas foram caracterizadas por difração de raios X (XRD), microscopia eletrônica de varredura (MEV) e microscopia eletrônica de transmissão (TEM). O método sonoquímico foi otimizado através do planejamento fatorial completo em dois níveis, onde se verificou que os parâmetros ciclo das ondas ultrassônicas e tempo influenciam significativamente no rendimento da reação. Fixando-se o ciclo em 80% e a amplitude em 20%, verificou-se que no tempo de reação de 15 min foram obtidas as nanopartículas com menor diâmetro médio (11,8 nm) e cristalinidade satisfatória. O método sonoquímico (15 min) foi comparado com o método de aquecimento convencional sob refluxo (90 min), mostrando-se mais rápido e eficiente na obtenção de nanopartículas com alta homogeneidade morfológica. O método sonoquímico produziu superestruturas tipo flor (3D) formadas pela agregação de nanobastões de Bi2S3 com diâmetro médio em torno de 11-15 nm. A morfologia e a qualidade dos nanocristais mostraram-se dependentes do tipo de solvente empregado na síntese. Superestruturas em 3D semelhantes a flores foram obtidas quando etilenoglicol puro foi usado como solvente, enquanto estruturas em 1D na forma de nanobastões foram obtidas quando se utilizou uma mistura de dimetilsulfóxido e etilenoglicol. Foi proposto um mecanismo para a síntese sonoquímica do Bi2S3 e os papéis do solvente e do surfactante nesta síntese foram discutido / Salvador

L'énergie, le développement durable et la santé sont au cœur des préoccupations actuelles de la planète. La disparition inéluctable des énergies fossiles, les conséquences graves des émissions de gaz carbonique sur l'environnement et la santé appellent des solutions rapides et efficaces pour suppléer aux premières et minimiser les autres.Parmi les solutions envisagées la catalyse hétérogènes représentés par les matériaux poreux, ces derniers ont prouvé leur efficacité, néanmoins des obstacles sont à corriger ou à contourner tel que le problème d'inaccessibilité des molécules encombrantes dans sites des micropores de ce matériau. Dans cette thèse nous avons essayé de trouver la solution à ce problème en travaillant sur des nanostructures ZSM-5.Dans une première étape, nous avons optimisé ce matériau en l'occurrence ZSM-5, avec une réduction de la taille des particules, d'une échelle microscopique vers une autre nanométrique, ce qui nous a permis d'augmenter la surface externe après une modification de certains paramètres. Dans la deuxième étape, et afin de donner une entité catalytique à notre support (la zéolithe), nous avons activé ce matériau par l'incorporation des cations, choisis en fonction d'une réaction bien spécifique, qui est celle d'oxydation des méthylènes benzéniques. Pour ce fait nous avons élaboré différents catalyseurs pour nos réactions.Nous avons conclu cette thèse par la catalyse avec la M-ZSM-5 (M = Cu, Cr et Fe) et une étude comparative est faite avec les MOFs qui portent les mêmes cations actifs dans leur partie minérale. / Energy, sustainable development, and health are at the heart of contemporary concerns of the planet. The inevitable disappearance of fossil fuels, the severe consequences of carbon emissions on the environment and health require quick and effective solutions to supplement the first and minimize others. Among the solutions proposed, there are porous materials which have proven their effectiveness; however, there are still obstacles to be corrected or circumvented. In this thesis, we focus on the problem of bulky molecules' inaccessibility in micro pores of the materials we wish to study. In the first part, we optimize the material in this case, ZSM-5, with a reduction in particle size to a microscopic scale to another nano, which allows us to increase the external surface after changing certain parameters. In the second step, in order to give a catalytic entity to our support (zeolite), we activate with this material incorporating cations selected according to a specific property of the benzyl methylenes oxidation reaction. For this reason we developed different method of preparation. We conclude this thesis by catalysis with M-ZSM-5 (M = Cu, Cr and Fe) and a comparative study on the method of preparation and the MOFs that bears the same cations as mineral part which constitutes the materials.

Semiconducting nanocrystals in open-access microcavities are promising systems in which enhanced light-matter interactions lead to quantum effects such as the modulation of the spontaneous emission process and exciton-polariton formation. In this thesis I present improvements of the open cavity platform which serves to confine the electromagnetic field with mode volumes down to the &lambda;³ regime and demonstrate results in both the weak and strong coupling regimes of cavity quantum electrodynamics with a range of different low-dimensional materials. I report cavity fabrication details allowing a peak finesse of 5 &times; 10⁴ and advanced photonic structures such as coupled cavities in the open cavity geometry. By incorporating two-dimensional materials and nanoplatelets in the cavity I demonstrate the strong coupling regime of light-matter interaction with the formation of exciton-polaritons, quasi-particles composed of both photon and exciton, at room temperature. In the perturbative weak coupling regime I show pronounced modulation of the single-photon emission from CdSe/ZnS quantum dots and the two-dimensional material WSe₂ and demonstrate Purcell enhancement of the spontaneous emission rate by factors of 2 at room temperature and 8 at low temperature. The findings presented in this thesis pave the way to establish open microcavities as a platform for a wide range of applications in nanophotonics and quantum information technologies.

The purpose of this study was to evaluate the performance of scanning mobility particle sizers in the characterization of nanoaerosols. A sampling chamber was constructed from aluminum and tempered glass, had a volume of 4.6 cubic feet, and was designed for the introduction of aerosols and dilution air, maintenance of aerosol concentration, and continuous exhaust of chamber air. Penetration and aerosol distribution tests were conducted within the chamber. An aerosol generation and measurement system comprised of nitrogen gas, BGI 3 jet Collison Nebulizer, diffusion dryer, aerosol charge neutralizer, mixing chamber, critical orifice, hygrometer, condensation particle counter, scanning mobility particle sizer, air sampling pump, air sampling cassettes, and a vacuum pump was assembled. A BGI 3 jet Collison Nebulizer was used to generate the nanoparticle aerosols. The two types of nanoparticle aerosols utilized in the experiment were salt (NaCl) and polystyrene latex (PSL) spheres. Relative humidity and temperature measurements were obtained within the chamber. Real-time, direct-reading particle measurement instruments including a condensation particle counter (CPC) (TSI, Model 3007), and three scanning mobility particle sizer (SMPS) instruments (Particle Measuring Systems, Nano-ID NPS500; TSI, NanoScan SMPS Nanoparticle Sizer Model 3910) were used for particle measurements. For each test run, two air samples were collected on membrane filters for electron microscopy (EM) analysis. Eight trials were conducted using NaCl nanoaerosols, and twelve trials were conducted using PSL spheres. The selected particle sizes for the experiments were 57 nm, 92 nm, 147 nm, and 220 nm. For the NaCl nanoaerosol suspensions, the SMPS lines of fit were log-normally distributed and predominantly parallel. The geometric standard deviation (GSD) of these distributions was approximately 1.7, which confirms that the distributions were approximately the same. In these experiments, instrument 3 identified a higher percentage of NaCl particles within the size range intervals of the selected NaCl size parameter, and the count median diameters (CMDs) for the instrument 3 measurements were closer to the selected NaCl size parameter more often than the other instruments. This suggests that instrument 3 was more responsive than the other instruments to the selected size range and the selected NaCl size parameters. The electron microscopy (EM) lines of fit for the NaCl experiments were predominantly parallel with the SMPS lines of fit, suggesting that the log-normally distributions are similar. The GSD of EM distributions was approximately 1.8, which confirms that the distributions were approximately the same as the SMPS distributions. Results from the regression plots demonstrated that the main effects and interaction were statistically significant with a p<0.0001. The coefficient of determination, R2, for the regression lines was 0.87. The post-hoc Tukey HSD results identified a significant difference between the instrument 3 dataset, and the datasets for instruments 1 and 2. For the PSL nanoaerosol suspensions, the SMPS lines of fit were log-normally distributed and predominantly parallel. The GSD of these distributions was approximately 1.3, which confirms that the distributions were approximately the same. In these experiments, instrument 2 identified a higher percentage of PSL particles within the size range intervals of the selected PSL size parameter, and instrument 2 CMDs were closer to the selected PSL size parameter more often than the other instruments. This suggests that instrument 2 was more responsive than the other instruments to the selected size range and the selected PSL size parameters. Results from the regression plots demonstrated that the main effects and interaction were statistically significant with a p<0.01. The coefficient of determination, R2, for the regression lines was 0.44. The post-hoc Tukey HSD test identified a significant difference between the instrument 3 dataset and the instrument 1 dataset. Potential sources of variability include solution water background contamination, surfactants in the PSL solution, and agglomeration. The performance of all the scanning mobility particle sizers compared in these experiments was acceptable for research and field applications, but caution should be taken when comparing the measurements of SMPS, especially SMPS from different manufacturers.

ANDRADE NETO, Davino Machado. Magnetic ressonance imaging contrast agents obtained by fast sonochemistry approach. 2016. 84 f. Dissertação (Mestrado em Química)-Universidade Federal do Ceará, Fortaleza, 2016. / Submitted by Aline Mendes (alinemendes.ufc@gmail.com) on 2017-01-25T19:35:32Z No. of bitstreams: 1 2016_dis_dmandradeneto.pdf: 4658452 bytes, checksum: 4d05fbe6bccc67518a89306c468793a6 (MD5) / Approved for entry into archive by Jairo Viana (jairo@ufc.br) on 2017-01-26T20:28:31Z (GMT) No. of bitstreams: 1 2016_dis_dmandradeneto.pdf: 4658452 bytes, checksum: 4d05fbe6bccc67518a89306c468793a6 (MD5) / Made available in DSpace on 2017-01-26T20:28:31Z (GMT). No. of bitstreams: 1 2016_dis_dmandradeneto.pdf: 4658452 bytes, checksum: 4d05fbe6bccc67518a89306c468793a6 (MD5) Previous issue date: 2016 / Functionalized Fe3O4 nanoparticles (NPs) have emerged as a promising contrast agent for magnetic resonance imaging (MRI). Their synthesis and functionalization methodology strongly affects their performance in vivo. Although thermal decomposition is the most commonly used growth methodology reported in the literature, it has proven to be time-consuming, expensive, and laborious. Therefore, this work describes a rapid and facile sonochemical methodology to synthesize and functionalize Fe3O4 NPs with excellent physico-chemical properties for MRI. In this work, a sonochemistry approach was used to produce, in 12 min, Fe3O4 NPs functionalized with polysodium acrylate (PAANa), trisodium citrate (CIT), branched polyethylenimine (BPEI), and sodium oleate. X-ray diffraction and transmission electron microscopy demonstrated that the NPs were composed of a single inverse spinel phase with an average diameter of 9–11 nm and a narrow size distribution. It was confirmed by Mössbauer spectroscopy and magnetic measurements that the obtained NPs were transitioning to the superparamagnetic regime and possessed excellent magnetization saturation values (59–77 emu/g). Fourier transform infrared spectroscopy proved that the sonochemistry approach provided conditions that induced a strong interaction between Fe3O4 and the capping agents. Furthermore, dynamic light scattering experiments evidenced that samples coated with PAANa, CIT, and BPEI possess colloidal stability in aqueous solvents. Emphasis must be placed on PAANa-coated NPs, which also presented remarkable colloidal stability under simulated physiological conditions. Finally, the obtained NPs exhibited great potential to be applied as an MRI contrast agent. The transverse relaxativity values of the NPs synthesized in this work (277–439 mM-1s-1) were greater than those of commercial NPs and those prepared using other methodologies. Therefore, this work represents significant progress in the preparation of Fe3O4 NPs, providing a method to prepare high-quality materials in a rapid, cost-effective, and facile manner. / Nanopartículas (NPs) funcionalizadas emergiram como promissores candidatos para serem aplicadas como agente de contraste para imagem por ressonância magnética nuclear e sua metodologia de síntese e funcionalização afetam fortemente sua performance in vivo. A metodologia mais utilizada para a produção dessas NPs funcionalizadas é a decomposição térmica, a qual tem provado ser financeiramente desfavorável, laboriosa além de requisitar longos tempos de execução. Portanto, este trabalho tem como objetivo descrever uma metodologia fácil e rápida, através do método sonoquímico, para a síntese e funcionalização de NPs de Fe3O4 com excelentes propriedades físico-químicas com objetivo de serem aplicadas como agente de contraste para imagem por ressonância magnética nuclear. Neste trabalho, o método sonoquímico foi usado para produzir, em 12 min, NPs de Fe3O4 funcionalizadas com policrilato de sódio, citrato de sódio, polietilenamina ramificada e oleato de sódio. Difração de raios-X e microscopia eletrônica de transmissão demonstraram que as NPs produzidas são compostas de uma única fase de espinélio inverso de 9-11 nm de diâmetro e uma distribuição de tamanho estreita. Foi confirmado por meio da espectroscopia Mössbauer e medidas magnéticas que as NPs sintetizadas estão em transição para o regime superparamagnético e que possuem excelente valor de magnetização de saturação (59-77 emu/g) para aplicações biomédicas. Espectroscopia de infravermelho por transformada de Fourier provou que a radiação sonoquímica forneceu condições adequadas para que acontecesse uma interação forte entre o núcleo magnéticos e os agentes fucionalizantes. Além disso, experimentos de espalhamento dinâmico de luz confirmaras que as amostras recobertas com moléculas orgânicas hidrofílicas possuem estabilidade coloidal em solventes aquosos. Destaque deve ser dado a nanopartícula magnética recoberta com poliacrilato de sódio, que demonstrou excelente estabilidade coloidal em condições fisiológicas simuladas. Finalmente, as NPs obtidas se mostraram serem promissores candidatos a agentes de contraste. Uma vez que seus valores de relaxatividade transversal foram maiores que os agentes de contraste comerciais e daqueles preparados por outras metodologias sintéticas. Portanto, este trabalho trás um grande avanço no que se refere a preparação de NPs de Fe3O4 funcionalizadas para aplicações biológicas, uma vez que materiais de alta qualidade foram preparados de forma rápida e fácil.

xvii, 203 p. / Gold nanoparticles have garnered recent attention due to their intriguing size- and shape-dependent properties. Routine access to well-defined gold nanoparticle samples in terms of core diameter, shape, peripheral functionality and purity is required in order to carry out fundamental studies of their properties and to utilize these properties in future applications. For this reason, the development of methods for preparing well-defined gold nanoparticle samples remains an area of active research in materials science. In this dissertation, two methods, diafiltration and aptamer mediated synthesis, are explored as possible routes towards well-defined gold nanoparticle samples. It is shown that diafiltration has considerable potential for the efficient and convenient purification and size separation of water-soluble nanoparticles. The suitability of diafiltration for (i) the purification of water-soluble gold nanoparticles, (ii) the separation of a bimodal distribution of nanoparticles into fractions, (iii) the fractionation of a polydisperse sample and (iv) the isolation of [rimers from monomers and aggregates is studied. NMR, thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS) measurements demonstrate that diafiltration produces highly pure nanoparticles. UV-visible spectroscopic and transmission electron microscopic analyses show that diafiltration offers the ability to separate nanoparticles of disparate core size, including linked nanoparticles. These results demonstrate the applicability of diafiltration for the rapid and green preparation of high-purity gold nanoparticle samples and the size separation of heterogeneous nanoparticle samples. In the second half of the dissertation, the identification of materials specific aptamers and their use to synthesize shaped gold nanoparticles is explored. The use of in vitro selection for identifying materials specific peptide and oligonucleotide aptamers is reviewed, outlining the specific requirements of in vitro selection for materials and the ways in which the field can be advanced. A promising new technique, in vitro selection on surfaces (ISOS), is developed and the discovery using ISOS of RNA aptamers that bind to evaporated gold is discussed. Analysis of the isolated gold binding RNA aptamers indicates that they are highly structured with single-stranded polyadenosine binding motifs. These aptamers, and similarly isolated peptide aptamers, are briefly explored for their ability to synthesize gold nanoparticles. This dissertation contains both previously published and unpublished co-authored material. / Adviser: James E. Hutchison