Project Presentation Day 2004
Mechancial Engineering Department
Materials Science and Engineering
April 20, 2004
Development and Characterization of Porous Inorganic-Organic Hybrid Structures Produced by Electrospinning
Winning Entry
Anthony Danna, Sarah Doherty, Justin MacEachern, Laura Matejik, Anissa Sidibe
The treatment of bone defects as a result of trauma or disease forms a major part of clinical medical practice. The major options available are: a) autografts b) allografts c) synthetic materials. Although autografts would be the ideal candidates for these applications, the limited supply of healthy donor tissue necessitates the development of other materials. Synthetic materials primarily based on a variety of calcium phosphates have been used clinically, with moderate success for over 20 years. These materials, however, do not mirror the inherent biological structure of the natural bone tissue and consequently, do not yield the desired results when used under in vivo conditions over extended periods. The objective of this study was to produce an organic-inorganic hybrid. A calcium phosphate (CP) -poly vinyl alcohol (PVA) hybrid was designed to mimic the inorganic and organic phases of natural bone. The hybrid was synthesized using a sol-gel method to produce a CP-PVA ratio which, when electrospun, maximized the CP concentration within the fibrous nanofiber structure. Using various techniques, such as DSC, XRD, IR, and SEM the electrospun structures were characterized. Once it was determined that the procedure produced a nanofibrous matrix, with a high CP concentration, the percentage of PVA was decreased to determine the lowest PVA to CP ratio. The material properties of the final product were analyzed to determine the applicability of the fibrous structures for orthopedic applications.
Advisor: Satya Shivkumar
Evaluation of Electospun Polymer Coatings on 316 Stainless Steel Meshes
Winning Entry
Lizabeth Caron, Melani Thomas, Katherine Youmans
Porous coatings are deposited onto metallic substrates to improve the performance of several biomedical applications. In comparison to other coating methods, electrospinning offers favorable conditions for producing polymer coatings on a variety of substrates to enhance their surface properties. This project explored the feasibility of electrospinning polystyrene coatings onto stainless steel meshes with varying conditions. After characterizing the coated substrates it was found that pore size and surface treatments affect the morphology, thickness and adhesion of the porous coatings.
Advisor: Satya Shivkumar
Production of Chitosan Particles through Electrospinning
Eun Kim, Joon Pyo Lee
Chitosan is a polysaccharide that has been used in many biomedical applications such as wound dressing, drug delivery, and scaffolds for tissue engineering. The purpose of this project was to produce and characterize chitosan particles through electrospinning. These experiments examined the different effects certain variables, such as temperature, concentration, needle size, and voltages, have on the size, shape, and morphology of the chitosan particles. The objective of these experiments was to set the best environment to successfully electrospin chitosan repeatedly. The effect of solvent evaporation rate on the production of dry particles was examined. Different concentrations of chitosan dissolved in a slightly acidic solution sprayed through an electrospraying machine were analyzed. The ideal conditions for the production of chitosan particles were formulated through the data. All experiments were conducted with the internal temperature of the electrospinning chamber at 42 8 C. Various solution concentrations of 5% acetic acid and chitosan (medium molecular weight) were used to conduct the experiments. The effects of concentration were evaluated by electrospraying different concentrations of solutions at a constant voltage. The effects of voltage were evaluated by applying varying voltages to different concentrations. Additionally, all experiments were run with a straight 18 G needle and one with a tapered tip. Electrosprayed particles were collected on a substrate of black stock paper and digital photographs were taken at incremental times, observing the evaporation process. Ideal conditions for producing the smallest possible chitosan particles involved maximizing the applied voltage to 30 kV using a concentration of 0.01 g/mL.
Advisor: Satya Shivkumar
Renaissance Armor and Modern Metallurgy
Erica Bartos
This Major Qualifying Project reveals the potential asset that modern-day metallurgy is to historical metal conservation. Today many types of research exist to obtain comprehensive information on the composition, properties and other microscopic details of a metal. This technology has yet to be thoroughly applied to historical artifacts. Different microscopy techniques, including Scanning Electron Microscopy, were used on a piece of Renaissance armor from Higgins Armory Museum to discover possible applications of modern metallurgical research to historical metal conservation.
Advisors: Diran Apelian and Yancy Riddle
Fuel Cell Materials
John Richardson
Gas diffusion layers are simple to the unassisted eye, but are quite complex due to their coatings and foam-like nature. These GDLs play an important role in a polymer electrolyte membrane fuel cell. To understand GDL behavior in an assembled fuel cell stack as they are pressed against adjacent components, a metallographic method was established. This allows SEM evaluation of the change in shape of the GDL due to compression, and compares it to computational results that were obtained previously.
Advisor: Isa Bar-On
Students at Work Conducting Their Research
Students at Work Conducting Their Research
Students at Work Conducting Their Research
Last modified: October 12, 2006 16:14:39