Polymer Science Commons^™

Effects Of Hofmeister Ions On Lower Critical Solution Temperatures Of Poly(N-Isopropylacrylamide) And Poly(Vinyl Methyl Ether), Joseph Joaquin

Williams Honors College, Honors Research Projects

The goal of this study is to compare how four different Hofmeister anions (Cl-, SCN-, F-, and I-) affect the Lower Critical Solution temperature (LCST) on two thermo-responsive polymers: poly(N-isopropylacrylamide) (pNIPAAM) and poly(vinyl methyl ether) (PVME). pNIPAAm is commonly used in the environmental applications such as monitoring, oil-water separations, or antifouling materials, and in medical industry from drug delivery to tissue engineering. When pNIPAAM or PVME reaches a temperature above their LCST, they become hydrophobic, and the polymer chains coiled, leading to their aqueous solutions turn opaque. PVME exhibits a similar LCST as that of pNIPAAM, so it can be …

Sulfonated Ionomer Composite Membranes For Use In Vanadium Redox Flow Batteries, Xueting Wang

All Dissertations

While vanadium redox flow batteries (VRFBs) have garnered significant attention as a promising scalable energy storage technology, the current membrane material used in this technology, Nafion™, suffers from high cross mixing of vanadium ions in the liquid electrolytes, directly impacting battery performance properties such as the voltage and coulombic efficiencies, as well as resulting in a reduction in the overall battery lifetime. The use of ionomer nancomposites has proven to be one promising route of directly addressing the issue of high ion crossover, though the mechanism by which the nanoparticles act to reduce crossover remains in open question. Herein, the …

Exploring Natural Raw Materials For The Development Of Hot Melt Adhesives For Linings Of Paintings, Erica Factor

Williams Honors College, Honors Research Projects

Natural raw materials will be explored for developing hot melt adhesives for the lining of paintings. The leading raw material is a natural resin called "Damar". This resin is obtained from the tree family Dipterocaupocea in India and Southeast Asia. This material has shown promising results from initial testing. Damar, with the potential for other natural raw materials, will be combined with synthetic ingredients to create sustainable formulations. The formulations will be tested on linen to replicate the application onto paintings. The sustainability, tackiness, texture, and overall performance of each formula will be considered. Once a formulation has been selected, …

Using Afm-Ir To Study Nanoscopic Phase Behavior Of Polymer Blends And Photovoltaic Bulk Heterojunctions, Nathaniel L. Prine

Dissertations

Conjugated polymers (CPs) and polymer blends harbor the potential for high-performance organic solar cells (OSCs) due to their short energy payback time, low cost, solution processability, lightweight attributes, and flexibility. However, OSCs suffer from poor thermal stability compared to their inorganic equivalents. This study explores the thermal instability of OSCs, focusing on phase separation of the photoactive layer under heat, resulting in morphology changes and degradation of power conversion efficiency (PCE). Utilizing atomic-force microscopy coupled with infrared spectroscopy (AFM-IR) and differential scanning calorimetry (DSC), we delve into thermal stability-morphology relationships to devise strategies to improve OSC blend durability under thermal …

Characterization Of Interlayer Laser Shock Peening During Fused Filament Fabrication Of Polylactic Acid (Pla), Fabien Denise

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

The field of additive manufacturing (AM) has gained a significant amount of popularity due to the increasing need for more sustainable manufacturing techniques and the adaptive development of complex product geometries. The problem is that AM parts routinely exhibit flaws or weaknesses that affect functionality or performance. Over the years, surface treatments have been developed to compensate certain flaws or weaknesses in manufactured products. Combining surface treatments with the modularity of additive manufacturing could lead to more adaptable and creative improvements of product functions in the future. The current work evaluates the feasibility of pursuing a new research axis in …

The Cosolvent And Association Effect On Polymer Behaviors, Xiangyu Zhang

Theses and Dissertations

The blending or mixing is extensively utilized in diverse processes of polymers to bring about advantageous properties, but the behavior becomes intriguing when associations are involved and multi-solvents are used. Explanations based on chemistry-specific arguments are less than satisfactory in abstracting essential features, and lack the general applicability across various systems. So, this work focuses on capturing the physical force governing the phenomenon of interest by using a generic model. Highly non-trivial behaviors of polymers are often observed in multi-solvent solutions. It is known that polymers swell and dissolve in good solvents, while they tend to collapse and aggregate in …

Beeswax Wraps As An Alternative To Single-Use Plastics, Sarah Skiver

Williams Honors College, Honors Research Projects

The project goal was to compare the food storage efficacy of sustainable beeswax wraps verses the single-use plastic methods of resealable plastic sandwich bags and plastic cling wrap. The goal was also to test the reusability of the beeswax wraps, as it is a key advantage of beeswax wraps that is advertised. The project purpose was to explore sustainable and eco-friendly alternatives to single use plastics, which are harmful to the environment in both their production and their disposal. Food spoilage was compared in beeswax wrap, plastic sandwich bags, and plastic cling wrap, and spoilage was also observed in a …

Sustainable Polylactic Acid Foam Development Through Solid-State Processing, Philip Onffroy

Honors Theses

Plastics play a vital role in global materials industries, but they contribute to environmental and ecological toxicity effects that accelerate climate change. One important category of plastic material is polymer foams, which have widespread applications in insulation, packaging, and storage. Current bio-based plastic foams that originate from natural, non-petroleum feedstocks are potential solutions but do not yet have adequate properties to supplant petrochemical-based plastic foams. This project aims to generate, test, and analyze bio-based polylactic acid (PLA) polymer foams developed through methods involving solid-state processing such as solid-state shear pulverization (SSSP) and cryogenic milling. SSSP has previously been shown to …

Wetting Transition On 3d-Printed Surfaces, Isabelle Moryan

Williams Honors College, Honors Research Projects

Taking the previous research conducted, this project aims to further the study and research of the wettability of surfaces. Surface features and types are important factors to their wettability. The geometric properties of a surface can make it more hydrophobic and hydrophilic. Extreme cases of hydrophobic and hydrophilic surfaces lead to water repulsion or water absorption, even under extreme conditions. The goal of this project is to gain further insight on how fabricated 3D-printed featured surfaces and examine the wetting transition on these surfaces. In particular, cylindrical pillars will be studied with varied pillar spacing, height and diameter. In addition, …

Amine-Functionalized Interpenetrating Polymer Networks For Co2 Capture, James Wills

Williams Honors College, Honors Research Projects

The research performed looked to advance the studies of vacuum swing absorption of Carbon Dioxide to help combat global climate change issues. The focus of the project was to create an anime-polymer sorbent that will weakly absorb and desorb CO2. The sorbent must be durable and be able to withstand multiple uses. The creation of a porous polymer matrix aided in the amines' ability to absorb CO2. Created samples underwent several qualitative and quantitative tests to determine their usefulness as an industrial sorbent. Infrared spectroscopy was used to study the effectiveness of the amine sorbents. Studying the changes in the …

Mimicking The Namib Desert Beetle With Hydrophilic And Hydrophobic Surfaces, Tyler Bracewell

Williams Honors College, Honors Research Projects

The Namib Desert beetle, Stenocara gracilipes, condenses fog that rolls in off the west coast of Namibia to provide itself with the water it needs for the day. By lifting its abdomen into the air to collect the water vapor, it condenses on hydrophilic bumps that are about 500μm in diameter and are spaced apart about 500-1500μm. Once the water reaches a critical size, the droplet rolls off the hydrophilic bump and onto the flat hydrophobic surface of the elytra. Since the beetle is angled with its abdomen in the air, the water rolls down to its mouth. A …

A Comparison Of Fiber Mat Thickness Measurement Techniques Using Laser Interferometry And Water Displacement, Ryan Seabeck

Williams Honors College, Honors Research Projects

Polymer fiber mats may often be very thin which leads to complications in measuring thickness. The thickness of fiber mats, however, is crucial in understanding their behavior. Thickness affects how well the mat works as a filter as well as the pressure drop across the mat, and herein lies the need for accurate measurement techniques. Currently two of the available techniques for measuring mat thickness are by laser interferometry[1] and by buoyancy force when submerged in water[2]. Instead of measuring the buoyancy force in this experiment, an enclosure intended to measure the thickness via water displacement was …

Filtration Apparatus Design For Oil-Water Separation Using Membranes And Sponges, Alec Jerger

Williams Honors College, Honors Research Projects

It can be difficult to separate water and oil emulsions through traditional filtration. Therefore, investigations of filtering using thermo-responsive (TR) polymers, in this case poly(vinyl methyl ether) (PVME), was conducted. It’s hypothesized that below its lower critical solution temperature (LCST), PVME has an affinity for water while oil substances do not. Above the LCST the opposite will be true. To verify this hypothesis, iterations of filtration designs were created to provide optimum control over the parameters to measure flow. The final optimized experimental apparatus was a Chromaflex glass column which was air tight and controlled all parameters besides fluid flow. …

Effects Of Crosslinking Conditions On Biofouling Of Polymer Substrates With A Hydrogel Layer, Laura Davila

Williams Honors College, Honors Research Projects

The introduction of a hydrogel coating to a surface has been looked at for different benefits. Certain hydrogels offer antifouling properties that are beneficial to different applications like medical components. Previous attempts (2) (3)have been done to introduce a hydrogel surface to plastic substrates. One of them is to use grafting brushes which works properly but it is not sufficient since the layer is too thin and therefore can be damaged. The second method have a bulkier coating without crosslinking. Opposite to grafting brushes this method has too thick of a layer. Additionally, there is no crosslink therefore the coating …

Methods For Film Coating Electrospun Fibers, Kristopher Dejean

Williams Honors College, Honors Research Projects

Electrospinning uses high voltages to form polymer nanofiber membranes. These membranes have potential for use in filtration, tissue engineering, drug delivery, and catalysis. The nonwoven fiber mat is malleable but has a low tensile strength compared to a solid film of the same polymer. Joining the fibers with a thin film is desired to balance the strength and flexibility. Three methods of producing a film on fiber membrane were tested. The techniques are spraying then melting, spin coating, and dip coating. Electrospinning setup conditions, solvent ratios, damage to fibers, and spin coating speeds were determined. Research was abruptly stopped and …

Self-Assembled Metal Nanoparticle/Polymer Nanocomposites As Nanoreactors For One-Pot Reactions, Andrew Harrison

Theses and Dissertations

Polymer nanoreactors incorporating gold nanoparticle catalysts were self-assembled via Flash Nanoprecipitation. The incorporated gold nanoparticles maintained catalytic activity, which was evaluated using reduction of 4-nitrophenol with sodium borohydride as a model reaction. The diffusion coefficient for 4-nitrophenol was determined by NMR and used to calculate the second Damköhler number, which indicated that the systems were not diffusion limited. Despite similar diffusion coefficients, catalytic performance was strongly affected by the co-precipitant. For example, the apparent reaction rate per surface area using castor oil was over 8-fold greater than polystyrene. Thus, we measured the partition coefficient of 4-nitrophenol between water and castor …

Production Optimization Of Ring-Banded Spherulitic Crystals Of Poly (3-Butylthiophene-2,5-Diyl) Using Controlled Solution Evaporation, Frederick Paul Henderson Iii

Materials Engineering

Conductive polymers can carry a charge due to the presence of excess electrons along the carbon backbone. By growing these polymers into crystals, the usual insulative isotropic matrix that polymers form will be replaced with anisotropic regions where conduction is possible parallel to the crystal lattice growth direction. In previous research, while growing sphere shaped crystals it was observed that a few would exhibit rings that formed parallel to the circumference of the sphere. In this project, the conditions to produce this ring structure were examined by looking at two polymer solutions (with carbon disulfide or dichlorobenzene as solvent) and …

Compression Set Improvement Of Thermoplastic Vulcanizates For High Temperature Tubing, Mitchell Valaitis

Williams Honors College, Honors Research Projects

It was hypothesized that increasing the curative level of the fluorocarbon rubber (FKM) used in manufacturing of thermoplastic vulcanizate (TPV) materials would decrease the compression set values of the TPV enough for it to be suitable as a flexible, lightweight alternative to high operating temperature thermoset rubber tubing currently being used for power steering hose. First, promising TPV formulations were identified by varying the polyamide (PA) and FKM used in a Brabender mixer. Four different types of polyamide and four different types of FKM were investigated, with two of the FKM types and one polyamide type identified as being promising. …

Multidimensional Mass Spectrometry Of Chemonic™ Ccg-6 Nonionic Surfactant With Separation By Polarity And Shape, Charles Johnson

Williams Honors College, Honors Research Projects

Chemonic™ CCG-6 surfactant is a water-soluble poly(ethylene glycol) (PEG) conjugated alkyl glyceride emollient. This surfactant exists as a complex mixture of a glycerol cores conjugated with poly(ethylene glycol) branches (PEGylation) that were partially esterified with caprylic (C8) and capric (C10) acids. These may be esterified on one, two, or all three arms of the glyceride. The architecture of the structures in this mixture was studied using multidimensional mass spectrometry (MS). Mass spectrometry was interfaced with ultra-performance liquid chromatography (UPLC) and ion mobility (IM) separation. The mixture was separated by reversed-phase LC, oligomers of the star-branched polymer were separated according to …

Definite Indefiniteness Of "Molecular Weight" As A Claim Term For Polymer-Related Patents, Ping-Hsun Chen

The Journal of Business, Entrepreneurship & the Law

The molecular weight of a polymer is not just a number for a single molecule. In fact, molecular weight measurement is based on a large volume of molecules of the same polymer. Due to the non-uniformity of molecular weights, there are several methods to measure an “average molecular weight” of a polymer. Unfortunately, the Federal Circuit in Teva Pharms. USA, Inc. v. Sandoz, Inc., 789 F.3d 1335 (Fed. Cir. 2015), held that the term “molecular weight” in several polymer claims was indefinite, because the term could mean either peak average molecular weight, number average molecular weight, or weight average molecular …

Evaporation-Induced Formation Of Well-Ordered Surface Patterns On Polymer Films, Wei Sun

Theses and Dissertations--Chemical and Materials Engineering

Various techniques of fabricating surface patterns of small scales have been widely studied due to the potential applications of surface patterns in a variety of areas. It is a challenge to fabricate well-ordered surface area efficiently and economically. Evaporation-induced surface patterning is a promising approach to fabricate well-ordered surface patterns over a large area at low cost. In this study, the evaporation-induced surface patterns with controllable geometrical characteristics have been constructed. The dewetting kinetics on deformable substrate is also investigated.

Using simple templates to control the geometry and the evaporation behavior of a droplet of volatile solvent, various gradient surface …

Synthesis And Characterization Of Chemically Functionalized Shape Memory Nanofoams For Unattended Sensing Applications, Anna Paola Soliani

All Dissertations

The work in this dissertation is devoted to the synthesis and characterization of novel materials for off-line unattended sensing: shape-memory grafted nanofoams. The fabrication process and characterization of highly efficient, polymeric nanosensor element with the ability to selectively detect analytes and retain memory of specific exposure events is reported. These shape memory nanofoams could potentially act as efficient and highly sensitive coatings for evanescent waveguide-based optical monitoring systems. On exposure to specific analytes, the polymeric coatings locally change their internal structure irreversibly at the nanolevel, affecting the local optical properties such as refractive index. Currently, enrichment polymer layers (EPLs) are …

A Soft Condensed Matter Approach Towards Mathematical Modelling Of Mass Transport And Swelling In Food Grains, Michael Chapwanya, N. Misra

Articles

Soft condensed matter (SCM) physics has recently gained importance for a large class of engineering materials. The treatment of food materials from a soft matter perspective, however, is only at the surface and is gaining importance for understanding the complex phenomena and structure of foods. In this work, we present a theoretical treatment of navy beans from a SCM perspective to describe the hydration kinetics. We solve the transport equations within a porous matrix and employ the Flory–Huggin’s equation for polymer–solvent mixture to balance the osmotic pressure. The swelling of the legume seed is modelled as a moving boundary with …

Optimizing Polymer Fluorescence For Explosives Detection, Rose K. Cersonsky

Honors Scholar Theses

Pyrene is commonly used for explosives detection, as when mixed with polystyrene, the fluorescence intensity of the resulting film can be used as an indicator of the presence of nitro-aromatic, nitro-ether, or nitro-amine explosives. Previous studieshave tested a three-component system including pyrene, polystyrene, and a salt, tetrabutylammonium hexafluorophosphate (TBAHP). From these previous studies, it has been seen that vapor pressure of the preparation area is a governing factor in the formation of excimers, which are instrumental in achieving and maintaining fluorescence intensity. In this study, three parameters – solution concentration, film thickness, and molecular weight of polystyrene are examined to …

Toward Polymer Coating With Easy Ice Release, Chenyu Wang

Theses and Dissertations

Minimizing adhesion of ice has been the subject of extensive studies for applications such aircraft wings, wind turbine blades spacecraft, power transmission wires, while a growing interest concerns coatings for aerospace applications. The work described here describes progress for coatings and ice release test method development over the last few years. Major achievements include: (1) New Rigid Adherent-Resistant Elastomers (RARE), (2) A new Epoxied Cylinder (EC) adhesion test, (3) Validation of an ice release test, and (4) Study of ice adhesion strength on coating thickness for a PDMS elastomer. Rigid Adhesion-Resistance Elastomers (RARE) are comprised of 3F 1 terminated with …

Optimization Of Polymer Separation By Gradient Polymer Elution Chromatography, Gideon R. Liem, Linda Nien-Hwa Wang

The Summer Undergraduate Research Fellowship (SURF) Symposium

High Performance Liquid Chromatography (HPLC) has been a versatile separation method for polymers for many years. Analysis of different polymers by HPLC is typically done by utilizing the differential solubility of the polymers by mixing a good solvent and an anti-solvent in various compositions. This method is called Gradient Polymer Elution Chromatography (GPEC). While GPEC has been used extensively, it commonly uses a linear gradient to separate components. Linear solvent gradients consume a lot of solvent and take a relatively long time (> 30 minutes) to complete. The goal of this study is to develop a step gradient from a …