The capability to easily and inexpensively fabricate microfluidic devices with negligible dependence on specialized laboratory equipment continues to be one of the primary forces driving the widespread use of plastic-based devices. These devices are typically produced as replicas of a rigid mold or master incorporating a negative image of the desired structures. The negative image is typically constructed from either thick photoresists or etched silicon substrates using conventional photolithographic fabrication processes. While these micromachining techniques are effective in constructing masters with micron-sized features, the need to produce masters rapidly in order to design, fabricate, and test microfluidic devices, is a major challenge in microfluidic technology. In this research, we use inexpensive photosensitized copper clad circuit board substrates to produce master molds using conventional printed circuit technology. The techniques provide the benefits of parallel fabrication associated with photolithography without the need for cleanroom facilities, thereby offering a degree of speed and simplicity that allows microfluidic master molds to be constructed in approximately 30 minutes in any laboratory. These techniques are used to produce a variety of microfluidic channel networks using PDMS (polydimethylsiloxane) and melt-processable plastic materials.

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This thesis describes the study of a variety of nanoscale materials and the development of novel synthetic strategies for their production. While the focus and bulk of this study have been directed specifically at subwavelength lithography, a significant portion of this thesis research involves nanoparticle synthesis, characterization, and functionalization. Put in very simple terms, optical lithography is a process where a beam of light, focused in a specific pattern, is used to generate a physical pattern on a solid substrate. This technology forms the basis for almost all microchip production in the world at the present time. As demand for faster and more powerful chips increases, the need to further miniaturize the patterns while minimizing cost has become very important. Multiple photochemical systems were developed in the search for non-reciprocal photochemistry at 193 nm to increase the resolution of lithographic processes at that wavelength. One approach, based on anthracene sensitization of sulfonium salts for acid generation, used photochemically reversible 4+4 aromatic cycloaddition reactions to introduce the non-linear photochemistry. A second approach took advantage of the photochemistry of N-methylphenothiazine and provided the first true example of a lithographically-relevant multi-photon acid generating process. Since all of the systems we studied used sulfonium salts as the acid generating species, we also looked at the photochemistry of the salts themselves. We evaluated the structural effects of the salts on their direct photochemistry and the implications for sensitized multi-photon photochemistry. We found that the identity of the anion plays a significant role in both processes and propose a new photochemical mechanism for acid generation that involves a charge transfer excitation process. We also describe the synthesis and characterization of novel fluorescent silver nanoparticles, both in solution and polymer films. We show that the fluorescent images can be patterned easily and preliminary results show that photolithography based on nanoparticle formation may be possible. This latter approach could provide a facile route to nanoparticle-embedded functional materials. This work with nanoparticles was inspired partly by earlier work, also presented herein, on semiconductor nanoparticles and their interactions with disulfide ligands.

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Thesis (M.S.)--Rochester Institute of Technology, 1981. / Typescript. Includes bibliographical references (leaves 162-163).

This thesis describes the study of a variety of nanoscale materials and the development of novel synthetic strategies for their production. While the focus and bulk of this study have been directed specifically at subwavelength lithography, a significant portion of this thesis research involves nanoparticle synthesis, characterization, and functionalization. Put in very simple terms, optical lithography is a process where a beam of light, focused in a specific pattern, is used to generate a physical pattern on a solid substrate. This technology forms the basis for almost all microchip production in the world at the present time. As demand for faster and more powerful chips increases, the need to further miniaturize the patterns while minimizing cost has become very important. Multiple photochemical systems were developed in the search for non-reciprocal photochemistry at 193 nm to increase the resolution of lithographic processes at that wavelength. One approach, based on anthracene sensitization of sulfonium salts for acid generation, used photochemically reversible 4+4 aromatic cycloaddition reactions to introduce the non-linear photochemistry. A second approach took advantage of the photochemistry of N-methylphenothiazine and provided the first true example of a lithographically-relevant multi-photon acid generating process. Since all of the systems we studied used sulfonium salts as the acid generating species, we also looked at the photochemistry of the salts themselves. We evaluated the structural effects of the salts on their direct photochemistry and the implications for sensitized multi-photon photochemistry. We found that the identity of the anion plays a significant role in both processes and propose a new photochemical mechanism for acid generation that involves a charge transfer excitation process. We also describe the synthesis and characterization of novel fluorescent silver nanoparticles, both in solution and polymer films. We show that the fluorescent images can be patterned easily and preliminary results show that photolithography based on nanoparticle formation may be possible. This latter approach could provide a facile route to nanoparticle-embedded functional materials. This work with nanoparticles was inspired partly by earlier work, also presented herein, on semiconductor nanoparticles and their interactions with disulfide ligands.

Lithography is a print medium which allows the artist almost complete freedom in terms of image development. It is the fastest growing art medium on the North American Continent. However, until now, this important print medium has virtually been ignored in the high schools. The reasons for the omission in the high school art programs are financial and technical. The traditional methods of establishing a lithography workshop requires a vast amount of money, usually much more than the average art department's budget could afford. The technical difficulties involved not only in setting up the workshop but also in the processing and printing of the lithographs seemed to have finished any furthur discussion of establishing facilities at the high school level. Drawing upon fourteen years acquaintance with lithography, the experience of setting up a lithographic workshop on a small budget and experience as a high school art teacher I am attempting in this thesis to provide alternate methods for establishing a lithographic program in the schools. The teacher, although he may be lacking in any technical knowledge of lithography, should be able to follow the instructions set down in the thesis and be able to start a litho program with his classes. Included in the thesis are instruction whereby the teacher can start his classes using almost soley the existing facilities found in most art rooms or he can, if budget allows, develope a full facility including all aspects of lithography. All the equipment has been built by the writer and all the procedures have been tested. I am sure that by diligently following the instructions any art teacher could provide an interesting and rewarding lithographic program for his students. / Education, Faculty of / Graduate

Indiana University-Purdue University Indianapolis (IUPUI) / Infrared (IR) polarizers have been widely used in military and commercial applications. Controlling the polarization of incident light is one of major issues in the detector systems. However, conventional polarimetric IR detectors require series of polarizers and optical components, which increase the volume and weight of the system. In this research, stacked 1-dimensional (1-D) subwavelength grating structures were studied to develop compact size IR polarimetric detector by using surface plasmonic polariton. Experimental parameters were optimized by Finite Difference Time Domain (FDTD) simulation. Effects of gold (Au) grating size, numbers of stacked gratings, and dielectric space height were tested in the FDTD study. The fabrication of grating layers was conducted by using nanoimprint lithography. The samples were characterized by scanning electron microscopy. IR transmissions in transverse magnetic (TM) and transverse electric (TE) modes were measured by Fourier transform infrared spectroscopy (FTIR).

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