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In this thesis, the successful fabrication of 3D-printed microfluidic devices will be discussed. Fabrication is performed with a low-cost commercially available stereolithographic 3D printer utilizing a custom PEGDA resin formulation tailored for low non-specific protein adsorption based on my colleagues' work [Rogers et al., Anal. Chem. 83, 6418 (2011)]. Horizontal microfluidic channels with designed rectangular cross sectional dimensions as small as 300 um wide and 150 um tall are printed with 100% yield, as are cylindrical vertical microfluidic channels with 300 um designed (334 um actual) diameters. Moreover, two different resins developed by our group are utilized in the process of 3D-printing which is the novel aspect about this thesis since other groups have not done research on this aspect of 3D-printing.

No description available.

No description available.

No description available.

Nos últimos anos, a impressão 3D vem se colocando como uma técnica fundamental na produção de novos biomateriais; a estereolitografia, em particular, permite que sejam impressos arcabouços para suporte celular de arquiteturas altamente complexas. Observa-se, todavia, uma oferta pouco significante de resinas passíveis de impressão, uma vez que o mesmo material deve reunir características como biocompatibilidade, biodegradabilidade e, em algumas técnicas de impressão, potencial fotocurável. Este trabalho concentrou-se em sintetizar poliésteres inéditos - derivados de pantenol - biodegradáveis e bioabsorvíveis via policondensação catalisada pela lipase B da Candida antarctica. Além disso, pretendeu-se incluir insaturações de modo a permitir fotorreticulação dos mesmos. Foram produzidos dois tipos de poliésteres insaturados: (1) com insaturações endo (pertencentes à cadeia principal do polímero), a partir de copolímeros produzidos de pantenol e mistura de diésteres saturados (adipato de dietila e sebacato de dietila) e diésteres insaturados (fumarato de dietila e glutaconato de dietila); (2) com insaturações exo (pertencentes às cadeias secundárias do polímero), a partir da acrilação da hidroxila secundária de pantenol de poliésteres saturados do mesmo. A caracterização por cromatografia de permeação em gel mostrou a produção de7 polímeros na faixa de massa molar entre 2000 e 5000 Da. Todas as estruturas foram confirmadas por 1H RMN. A fotocura do material foi testada a partir de soluções dos poliésteres contendo fotoiniciador (BAPO) e correticulantes (NIPAM, NVPM e VIM). Após irradiação com radiação UV em 254 nm por diferentes tempos, foram produzidos filmes que puderam ter sua fração sol/gel determinadas, bem como suas características de intumescimento. Além de serem os primeiros poliésteres de pantenol observados até o momento na literatura, os materiais sintetizados neste trabalho provaram potencial de uso em impressoras 3D, visto que foram produzidos filmes fotorreticulados após cerca de 1 minuto de irradiação. / This work focused on synthesizing unpublished biodegradable and bioabsorbable panthenol-derived polyesters via polycondensation catalyzed by Candida antarctica lipase B. In addition, it was intended to include unsaturations to enable photocrosslinking in the final material. Two types of unsaturated polyesters were synthesized: (1) with unsaturations \"endo\" (belonging to the main polymer chain), from copolymers made of panthenol and mixtures of saturated diesters (adipate, diethyl sebacate and diethyl) and unsaturated diesters (diethyl fumarate and diethyl glutaconate); (2) with \"exo\" unsaturations (not in the main polymer chain), from the acrylation of the secondary panthenol hydroxyl group of the first saturated polyester.9 Characterization by gel permeation chromatography showed the production of polymers in the range of molar mass between 2000 and 5000 Da. All structures were confirmed by 1 H NMR. The photocrosslinking capability of the material was tested from polyester solutions containing photoinitiator (BAPO) and crosslinkers (NIPAM, NVPM, and VIM). After irradiation with UV radiation at 254 nm for different times, films were produced that could have their sol / gel fraction determined, as well as their swelling characteristics. In addition to being the first panthenol polyesters observed so far in the literature, the materials synthesized in this work proved potential use in 3D printers since photocrosslinked films were produced after about 1 minute of irradiation.

Modern Rapid Prototyping (RP) technology has been available for more than a decade and has aided in shortening product development times and costs in the manufacturing sector. Stereolithography (SL), the most mature of RP technology, has primarily been used to build small to medium sized parts although there are largescale applications i.e. the automotive industry that uses “mammoth SLA”. Recent developments in SL have been aimed at increasing the speed of the additive process of most SL apparatus (SLA). Developments include the chemistry of photopolymer resins, integral-curing processes as opposed to vector-by-vector processes, and what is now called microstereolithography. Integral curing has been made possible by the advent of dynamic masking generators such as liquid crystal displays (LCDs) and digital micromirror devices (DMDs). Much of the theory for this new layering process has been applied to the micro-scale and awaits application for medium to large sized parts. The Limaye Model was applied to a microstereolithography apparatus (µSLA) and used as a process planning method for curing dimensionally accurate micro parts. Examination of the results of this mathematical model shows an irradiance map simulating the irradiances on the resin surface. The light is expected to attenuate from the central axis according to a measured irradiance curve. Improvements can be made to the Limaye Model to make it applicable for the process planning of medium to large parts. It is the aim of this research to present an improved mathematical model of the Limaye Model, so that a given irradiance map will produce an evenly distributed irradiance and account for errors in the optical imaging system. It is hoped that the field of exposure of 200mm x 270mm or larger will be achieved.

Digital Clay represents a new type of 3-D human-computer interface device that enables tactile and haptic interactions. The Digital Clay kinematics structure is computer controlled and can be commanded to acquire a wide variety of desired shapes (shape display), or be deformed by the user in a manner similar to that of real clay (shape editing). The design of the structure went through various modifications where we finally settled on a crust matrix of spherical joint unit cells. After designing the kinematics structure, the next step is predicting the deformation of the crust matrix based upon a handful of inputs. One possible solution for predicting the shape outcome is considering minimizing the potential energy of the system. In this thesis two methods will be introduced. The first method will be an abstract model of the crust where the energy is calculated from a simplified model with one type of angular springs. The second method is the actual manufacturable crust model with two types of angular springs. From the implementation of these two methods, the output will be center-points of the unit cells. From the center-points, one can also calculate the joint angles within each unit cell.

Conventional solder balls used in microelectronic packaging suffer from thermo- mechanical damage due to difference in coefficient of thermal expansion between the die and the substrate or the substrate and the board. Compliant interconnects are replacements for solder balls which accommodate this differential displacement by mechanically decoupling the die from the substrate or the substrate from the board and aim to improve overall reliability and life of the microelectronic component. Research is being conducted to develop compliant interconnect structures which offer good mechanical compliance without adversely affecting electrical performance, thus obtaining good thermo-mechanical reliability. However, little information is available regarding the behavior of compliant interconnects under shock and impact loads. The objective of this thesis is to study the response of a proposed multi-path compliant interconnect structure when subjected to shock and impact loading. As part of this work, scaled-up substrate-compliant interconnect-die assemblies will be fabricated through stereolithography techniques. These scaled-up prototypes will be subjected to experimental drop testing. Accelerometers will be placed on the board, and strain gauges will be attached to the board and the die at various locations. The samples will be dropped from different heights to different shock levels in the components, according to Joint Electron Devices Engineering Council (JEDEC) standards. In parallel to such experiments with compliant interconnects, similar experiments with scaled-up solder bump interconnects will also be conducted. The strain and acceleration response of the compliant interconnect assemblies will be compared against the results from solder bump interconnects. Simulations will also be carried out to mimic the experimental conditions and to gain a better understanding of the overall response of the compliant interconnects under shock and impact loading. The findings from this study will be helpful for improving the reliability of compliant interconnects under dynamic mechanical loading.

Flammable solvents contained in liquid electrolytes pose a serious safety risk when used in lithium batteries. Oxide ceramic electrolytes are a safer alternative, but suffer from inadequate mechanical properties and ionic conductivity. Thin electrolyte layers resolve the issue of conductance, but accentuate the detrimental mechanical properties of oxide ceramics. The presented work has investigated oxide ceramic electrolyte reinforcement in composite electrolytes for all-solid-state batteries. Fabricating oxide ceramic electrolytes with engineered microstructure enabled development of a reinforced composite. This approach is based on the formation of 3D- porous ceramics via stereolithography printing of polymer templates from designed cubic, gyroid, diamond and bijel architectures. The microstructural parameters of templates were analysed and modified using computational techniques. Infiltration of the prepared 3D-porous electrolyte with polymeric-fibre reinforcement created the reinforced composite electrolyte. The prepared ceramic composite showed excellent reproduction of the template microstructure, good retention of ionic conductivity and enhanced mechanical properties. The final composite was composed of NASICON-type Li_1.6Al_0.6Ge_1.4(PO₄)₃ oxide ceramic electrolyte and epoxy and aramid fibre reinforcement. The gyroid architecture was computationally determined as having the optimal stress transfer efficiency between two phases. The printed gyroid polymer template gave excellent pore microstructure reproduction in ceramic that had 3D-interconnected porosity, high relative density and the most uniform thickness distribution. The ceramic matrix porosity allowed for complete infiltration of reinforcement by aramid and epoxy forming the fibre-reinforced ceramic matrix composite. The interpenetrating composite microstructure with ceramic and epoxy gave a flexural strength increase of 45.65 MPa compared to the ceramic. Unfortunately, the infiltration procedure of aramid-epoxy reinforcement did not realise the full tensile strength potential of aramid fibres.