Chemistry Commons^™

Modified-Electrodes For Redox-Magnetohydrodynamic (Mhd) Pumping For Microfluidic Applications, Christena Kayl Nash

Graduate Theses and Dissertations

A new microfluidic pumping and stirring technique was demonstrated for lab-on-a-chip applications. Microfluidics was accomplished via redox-MHD, which takes advantage of a body force (F_B) that is generated when there is a net movement of ions in solution (j) in the presence of a perpendicular magnetic field (B), according to the equation F_B = j×B. In this work the movement of ions in solution was generated using electrodes modified with the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) rather than a redox species in solution, which can interfere with analyte detection and with biological species. …

Poly (N-Isopropylacrylamide) Microgel-Based Thin Film Actuators For Humidity Sensing, Molla R. Islam, Michael J. Serpe

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

In this submission we fabricated a humidity-responsive polymer-based actuator by layering negatively charged poly(N-isopropylacrylamide)-co-acrylic acid microgels and positively charged poly(diallyldimethyl ammonium chloride) on top of a flexible plastic substrate. We show that the extent of the actuation (bending) was dependent on the atmospheric humidity. This property was used to detect atmospheric humidity by hanging weights from the actuator, which were rested on the pan of a top loading balance. This was done in such a way that the amount of the mass resting on the balance depended on the extent of actuator bending, which could then be related to humidity. …

Light Switchable Optical Materials From Azobenzene Crosslinked Poly (N-Isopropylacrylamide)-Based Microgels, Qiang Matthew Zhang, Xue Li, Molla R. Islam, Menglian Wei, Michael J. Serpe

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

4,4′-Di(acrylamido)-azobenzene was used as a crosslinker in poly(N-isopropylacrylamide)-based microgels. The microgels were subsequently used to fabricate microgel-based optical materials (etalons), which exhibited optical properties that were switchable upon exposure to UV irradiation. We also show that the extent of the response depended on the UV exposure time. These materials could find applications for controlled/triggered drug delivery, as well as in various optical applications.

Correlating Molecular Architecture Of A Radical Polymer Based Copolymer With Its Electrical Transport Properties, Holly Chan

Open Access Theses

The design and synthesis of electrically-conductive macromolecules can lead to significant improvements in the performance of polymer-based energy conversion devices (e.g., thermoelectric devices). For these organic electronic devices, conjugated polymers have dominated the area of conductive polymers; however, these materials are usually synthesized using conditions that lead to poorly-defined polymers. Furthermore, in these increasingly-standard polymers, the charge transport ability of the polymer thin films is largely affected by the degree of crystallinity, which is a difficult property to control in a reproducible fashion. Therefore, we seek to explore a new class of amorphous, non-conjugated polymers containing a stable radical …

A Novel Label-Free Colorimetric Assay For Dna Concentration In Solution, Molla R. Islam, Michael J. Serpe

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Optical devices were fabricated by sandwiching a “monolithic” poly(N-isopropylacrylamide-co-N-(3-aminopropyl) methacrylamide hydrochloride) (pNIPAm-co-APMAH) microgel layer between two semitransparent Au layers. These devices, referred to as etalons, exhibit characteristic multipeak reflectance spectra, and the position of the peaks in the spectra primarily depends on the distance between the Au surfaces mediated by the microgel layer thickness. Here, we show that the positively charged microgel layer can collapse in the presence of negatively charged single stranded DNA (ssDNA) due to ssDNA induced microgel crosslinking. The collapse results in a change in the etalon's optical properties, which can be used to detect target DNA …

Development And Implementation Of Dispersion Phase Diagrams (Dpds) For Four Different Hydrophobically Modified Ethoxylated Urethane (Heur) Based Acrylic Paint Systems, Tyler J. Bell

Master's Theses

Latex polymers serve as binders in a wide range of architectural paints and coatings. A latex is an aqueous colloidal dispersion of polymer particles that when dried above the polymer’s film formation temperature coalesces into a dry polymer film (Dragnevski, Routh, Murray, & Donald, 2010). The other main components of paint include associative thickeners, surfactants, pigments and fillers with the thickener being the primary area of focus for this study.

The relatively simple system of latex, associative thickener and surfactant has been studied extensively. These studies have shown the mechanism of thickening for the associative thickener, and surfactant effects on …

An Investigation Of Poly(N-Isopropylacrylamide) For Applications With Microfluidic Paper-Based Analytical Devices, Haydn Thomas Mitchell

Master's Theses

N,N′-methylenebisacrylamide-crosslinked poly(N-isopropylacrylamide), also known as P(NIPAM), was developed as a fluid delivery system for use with microfluidic paper-based analytical devices (microPADs). MicroPADs are postage-stamp-sized devices made out of paper that can be used as platforms for low-cost, simple-to-use point-of-care diagnostic assays. P(NIPAM) is a thermally responsive polymer that absorbs aqueous solutions at room temperature and will expel the solutions to microPADs when heated. The fluid delivery characteristics of P(NIPAM) were assessed, and P(NIPAM) was able to deliver multiple solutions to microPADs in specific sequences or simultaneously in a laminar-flow configuration. P(NIPAM) was then shown to be suitable …

Improving Hybrid Solar Cells: Overcoming Charge Extraction Issues In Bulk Mixtures Of Polythiophenes And Zinc Oxide Nanostructures, Grant T. Olson

Master's Theses

Organic photovoltaics (OPVs) have received a great deal of focus in recent years as a possible alternative to expensive silicon based solar technology. Current challenges for organic photovoltaics are centered around improving their lifetimes and increasing their power conversion efficiencies. One approach to improving the lifetime of such devices has been the inclusion of inorganic metal oxide layers, but interaction between the metal oxides and common conjugated polymers is not favorable. Here we present two methods by which the interactions between polythiophenes and nanostructured ZnO can be made to be more favorable. Using the first method, direct side on attachment …

Poly (N-Isopropylacrylamide) Microgel-Based Optical Devices For Sensing And Biosensing, Molla R. Islam, Andrews Ahiabu, Xue Li, Michael J. Serpe

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Responsive polymer-based materials have found numerous applications due to their ease of synthesis and the variety of stimuli that they can be made responsive to. In this review, we highlight the group’s efforts utilizing thermoresponsive poly (N-isopropylacrylamide) (pNIPAm) microgel-based optical devices for various sensing and biosensing applications.

Synthesis And Characterization Of Some Thallium Salt Complexes, Levi Dopierala

Masters Theses & Specialist Projects

Research into conductive organic and organometallic polymers began in 1977 when Heeger, Macdiarmid, and Shirakawa first doped polyacteylene with Iodine. They found that this doping granted the polymer metallic properties increasing conductivity by 11 orders of magnitude.[1] Unfortunately, polyacteylene is highly air-sensitive making it difficult to work with and limiting its applications. Therefore, current research is focused on synthesizing new organic and organometallic conductive polymers. The drive to discover these new polymers stems from their application flexibility and their low production cost.

Reported here is the synthesis of novel organometallic polymer precursors. Lead by Dr. Chad Snyder a library of …

Raft Polymerization Of Sulfonamide-Containing Methacrylamides, Michael B. Sims

Honors Theses

Targeted delivery of cancer therapeutics offers an exciting new opportunity for utilization of controlled polymerization techniques. However, a major obstacle in achieving the desired therapeutic effect is facilitating endosomal release of active agents following endocytosis. Peptides and pH-responsive polymers have been utilized as a means of triggering endosomal release via phase transition-induced membrane disruption. Unfortunately, the fidelity by which the pKa of these polymers/peptides can be varied is limited, such that it reduces their versatility in altering the phase transition point to best match the endosomal pH of a particular cell-type. Herein, we report the controlled polymerization of library of …

Effects Of Varying The Cure Profiles Of An Epoxy-Amine System, Patrick W. Hollingsworth

Honors Theses

The cure of an epoxy prepolymer with an amine hardener induces stress in thermosetting systems. The extent of residual stresses in the cured epoxy-amine thermosets are dependent on several factors; one of which is the cure profile utilized. The effect of cure profile on cure induced stresses of an epoxy-amine thermoset was examined in the current study. A difunctional epoxide based on diglycidyl ether of bisphenol-A (DGEBA) and a tetrafunctional amine curative were used to conduct this study. Two cure profiles were selected to prepare samples of varying degrees of stress in the cured thermosets. The first was constant heating …

Porphyrin Cross-Linkers For Generating Soluble Molecularly Imprinted Polymers From Polyethyleneimine, Mohammed R. Elshaer

Seton Hall University Dissertations and Theses (ETDs)

Molecular recognition is vital to many biochemical processes and is at the heart of promising bio-medically related technologies. Molecular imprinting has a long-standing history as a successful method for mimicking the molecular recognition phenomena exhibited by nature, whereby artificial receptors are prepared for a given target molecule based on synthetic polymers. The molecularly imprinted polymer (MIP) contains a three dimensional network with a memorized cavity specific to the shape and functionality of the templated target molecule. The utility of traditional MIPs has been limited due to an inherent lack of solubility. We have worked toward developing a system that allows …

Study Of The Structure-Property Relationships That Determine The Effects Of Latexes And Starch Containing Latex Emulsions On The Performance Of The Barrier Coatings (Sub-Coat) For Paper, Joanna Marie Monfils

Master's Theses

The history of carbonless paper dates back to the 1940s. Before this, a carbon copy sheet was needed between sheets of paper to be able to produce one or more copies simultaneously during writing. The pressure from a pen or typewriter would help deposit the ink of the carbon paper onto the blank sheet of paper under the original written sheet to create a “carbon copy.” This method did however, have its disadvantages. Not only did it produce a limited number of copies, but it was also a messy process. So came the creative process of using microencapsulated dyes to …

Classification Of Biorenewable Multiblock Copolymers, Sean Pickthorn

Celebrating Scholarship & Creativity Day (2011-2017)

Recent advances in polymer production sciences have led to an increase in research in sustainable practices. Our efforts intended to produce a toughened biorenewable multiblock copolymer. Polylactide has been noted to be produced by sustainable practices but is limited because of the fragile structure. To improve the brittle behavior of polylactide, preparation of polylactide-b-polybutadiene-b-polylactide multiblock copolymers were synthesized with a fixed weight of dihydroxyl polybutadiene (~3000 and ~2000g/mole series) and variable volume percent (50-90%) of both semicrystalline poly(L-lactide) and amorphous poly(D,L-lactide). Producing a multiblock copolymer intended to strengthen the mechanical properties by bridging and gapping over several domains. Initially, triblock …

Effect Of Multivalent Ions On The Swelling And Mechanical Behavior Of Superabsorbent Polymers (Saps) For Mitigation Of Mortar Autogenous Shrinkage, Qian Zhu

Open Access Theses

The chemical and physical structure-property relationships of model superabsorbent polymer (SAP) hydrogels were characterized with respect to swelling behavior and mechanical properties in different ionic solutions (Na+ , Ca2+ , and Al3+ ). The model hydrogels were composed of poly(sodium acrylate-acrylamide) (PANa-PAM) copolymer with varying concentrations of PANa (0, 17, 33, 67, and 83 wt.%) and covalent crosslinking densities of 1, 1.5, and 2 wt.%. By synthesizing the hydrogels in-house, systems with independently tunable amounts of covalent crosslinking and anionic functional groups were created, allowing for the relative effects of covalent and ionic crosslinking on the properties of the hydrogels …

Synthesis And Polymerization Of (E,E)-[6.2]-(2,5)Furanophane-1,5-Diene, Neil D. Doppler, Jeffrey H. Glans

Chemistry & Physics Faculty Publications

The goal of this research is to polymerize (E,E)-[6.2]-(2,5)furanophane to give a linear polymer. It will be synthesized by a 1,8-Hofmann Elimination using trimethyl-[(E)-3-(5-methyl-2-furyl)allyl] ammonium iodide. This diene will then be polymerized. The resulting polymeric [3.2] furanophane will then be oxidized to form a polymeric macrocycle tetra ketone. This compound will be tested for cation complexation.

Responsive Polymers For Biosensing And Protein Delivery, Molla R. Islam, Yongfeng Gao, Xue Li, Michael J. Serpe

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

In this feature article, we review some of the most recent advances in the field of materials chemistry for biosensing, disease diagnostics, and drug delivery. Our recent work on the development of responsive polymer-based platforms for biosensing and drug delivery will also be highlighted. This feature article is meant to outline the breadth of the utility of polymer-based materials for select applications, as well as their enormous potential impact on future technologies.

Degradation Of High Voltage Glass Fiber-Reinforced Polymer Matrix Composites By Aggressive Environmental Conditions, Tianyi Lu

Electronic Theses and Dissertations

Polymer matrix composites reinforced with either E glass or ECR glass fibers-reinforced are used in a variety of high voltage electrical applications because of their advantages like lower weight and cost. However, they can be damaged by aggressive in-service conditions such as high temperature, ultraviolet radiation, moisture, ozone and corrosive environments. Different degradation mechanisms can develop in high voltage PMCs under those extreme environments, which, in turn, can affect the long term structural durability of the composites. A set of PMCs reinforced with ECR-glass and E-glass fibers embedded in four different resins has been investigated in this study. In addition, …

Microwave Assisted Chemical Synthesis Using Polydimethylsiloxane, Omniya Alomainy

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.

Sustainable Thermoplastic Elastomers Derived From Renewable Cellulose, Rosin And Fatty Acids, Y. Liu, K. Yao, Xiaoming Chen, Jifu Wang, Zhongkai Wang, Harry J. Ploehn, C. Wang, F. Chu, Chuanbing Tang

Faculty Publications

Two series of graft copolymers, cellulose-g-poly(n-butyl acrylate-co-dehydroabietic ethyl methacrylate) (Cell-g-P(BA-co-DAEMA)) and cellulose-g-poly(lauryl methacrylate-co-dehydroabietic ethyl methacrylate) (Cell-g-P(LMA-co-DAEMA)), were prepared by “grafting from” atom transfer radical polymerization (ATRP). In these novel graft copolymers, cellulose, DAEMA (derived from rosin), and LMA (derived from fatty acids) are all sourced from renewable natural resources. The “grafting from” ATRP strategy allows the preparation of high molecular weight graft copolymers consisting of a cellulose main chain with acrylate copolymer side chains. By manipulating the monomer ratios in the P(BA- …

Addressing Public Health Risks Of Persistent Pollutants Through Nutritional Modulation And Biomimetic Nanocomposite Remediation Platforms, Bradley J. Newsome

Theses and Dissertations--Chemistry

Due to their relative chemical stability and ubiquity in the environment, chlorinated organic contaminants such as polychlorinated biphenyls (PCBs) pose significant health risks and enduring remediation challenges. Engineered nanoparticles (NPs) provide a novel platform for sensing/remediation of these toxicants, in addition to the growing use of NPs in many industrial and biomedical applications, but there remains concern for their potential long-term health effects. Research highlighted herein also represents a transdisciplinary approach to address human health challenges associated with exposure to PCBs and NPs. The objectives of this dissertation research are two-fold, 1) to develop effective methods for capture/sensing and remediation …

Tandem Mass Spectrometry Of Multiply Charged Polymers: Using Ms3 Strategies For Full Structural Characterization Of Polyacrylamides, Paul M. Krauss

Williams Honors College, Honors Research Projects

In mass spectrometry, a compound is taken and converted into a gas-phase ion by an electrical charge (Balogh, 2009). From these ions, a chart is then created that displays the mass to charge ratio, which is able to then be analyzed to find out the charge of the ions, as well as the mass of the compound (Balogh, 2009). One specific type of mass spectrometry there is available is known as a fragmentation spectrometry. In fragmentation spectrometry, the molecule is not only ionized and analyzed, but fragmented parts that are formed into ions are also ionized and analyzed. This is …

Mechanical And Thermal Properties Of Polylactide/Polymeric Plasticizers, Wanlapha Apising

Chulalongkorn University Theses and Dissertations (Chula ETD)

The current study focused on flexibility improvement of polylactide by using three new types of plasticizers: diethyl succinate, glycerol ethoxylate, poly(di(ethylene glycol)adipate). The plasticizer concentrations were varied depending on each type. Mechanical property of the plasticized polymers was investigated. It was found that elongation at break of the plasticized polymers was increased, whereas tensile strength and Young’s modulus were decreased. The plasticized polymer with diethyl succinate exhibited the highest elongation at break. Thermal property of the plasticized polymers containing glycerol ethoxylate yielded the lowest Tg and Tc. When the plasticizers were added, thermal property was reduced, in which the plasticized …

Dry Reforming Of Methane In Palladium-Silver-Copper Alloy Membrane Reactor, Sarocha Sumrunronnasak

Chulalongkorn University Theses and Dissertations (Chula ETD)

PdAgCu ternary alloy membranes were prepared by the sequential electroless plating of Pd following by electroplating of Ag and Cu onto stainless steel support. The metal composition of the membrane was varied by changing the metal deposition times. The fabricated membranes were then annealed at various temperatures from 500 °C to 600 °C under argon atmosphere in order to form the alloys for 20 to 120 hrs. The Energy Dispersive X-ray spectroscopy (EDX) and X-Ray Diffraction (XRD) were employed to investigate the element distribution in the membrane which provided the insight of the alloying formation. Complete formation of the alloy …

Preparation Of Polylactide/ Polycaprolactone/Hydroxyapatite Particles, Walaiporn Nguantanom

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research focused on preparation of polylactide/polycaprolactone/hydroxyapatite particles by using the solvent evaporation method. The effects of HA loadings varied in a range of 10-40 wt% and blending ratios between PLA and PCL on the size distribution, morphology, and thermal properties of the composite films were investigated. The results showed that the size distributions of the composite particles were composed of both small and large particles, depending on the HA concentration and blending ratio of PLA/PCL. The addition of HA at 10 wt% exhibited a strong influence on the size distribution of microspheres, while the PLA/PCL blend tended to produce …

Synthesis Of Poly(N-Isopropylacrylamide)-Based Nanogels Via Differential Microemulsion Polymerization For Drug Delivery Systems, Meshaya Pruettiphap

Chulalongkorn University Theses and Dissertations (Chula ETD)

This thesis is to study the synthesis of poly(N-isopropylacrylamide-co-protic acid) nanogels and their performance to be used as drug delivery carriers. The objective is to achieve thermal/pH-responsive nanogels with a lower critical solution temperature (LCST) close to human body temperature. Differential microemulsion polymerization (DMP) technique, which has been considered the best one to produce nanoparticles of a high solid content with a low surfactant amount, was applied. Specifically, one-step DMP was used for synthesizing poly(N-isopropylacrylamide) (PNIPAM) preparation while two-step DMP was adopted to synthesize poly[N-isopropylacrylamide-co-(acrylic acid)] (poly(NIPAM-co-AA)) and poly[N-isopropylacrylamide-co-(itaconic acid)] (poly(NIPAM-co-IA)) nanogels, in which sodium dodecyl sulphate (SDS) was used …

Form Factor Of Pnipam Microgels In Overpacked States, U. Gasser, J. S. Hyatt, J.- J. Lietor-Santos, E. S. Herman, L. Andrew Lyon, A. Fernandez-Nieves

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

We study the form factor of thermoresponsive microgels based on poly(N-isopropylacrylamide) at high generalized volume fractions, ζ, where the particles must shrink or interpenetrate to fit into the available space. Small-angle neutron scattering with contrast matching techniques is used to determine the particle form factor. We find that the particle size is constant up to a volume fraction roughly between random close packing and space filling. Beyond this point, the particle size decreases with increasing particle concentration; this decrease is found to occur with little interpenetration. Noteworthily, the suspensions remain liquid-like for ζ larger than 1, emphasizing the importance of …

Nanoparticles And Polymer Crystallization Kinetics In Hybrid Electronic Devices, Taylor William Wagner

Master's Theses

Conjugated semi-conducting polymers have become well known for their potential applications in hybrid electronic devices like solar cells, LEDs, and organic displays. These hybrid devices also contain inorganic nanoparticles, which complement the polymer when they are combined into the same layer. Control over the conformation and crystallinity of the polymer is critical for device performance, yet not much is known about the effect that these nanoparticles have on the polymer. Here, zinc oxide nanowire was surface modified with mono-substituted-carboxylic acid tetraphenylporphyrin and dodecanethiol, and introduced to poly(3-hexyl thiophene) in solution. The electron transfer, kinetics, and thermodynamics of this system were …

Morphology And Conformation Of Polythiophene Derivatives In Anisotropic Core-Shell Nanocomposites And Solution, Neil Redeker

Master's Theses

Conjugated semiconducting polymers have garnered substantial interest in recent years due to the potential for use in various applications, particularly in the field of electronic devices such as photovoltaic cells and light emitting diodes. Conjugated polymers offer numerous advantages in these applications, including low cost and high flexibility, but electronic devices based on these materials are currently limited by poor performance. Because of these limitations, increased focus has been placed on improving conjugated polymers for use in commercially viable products. Here, a novel core shell hybrid nanocomposite based on anisotropic zinc oxide nanowires and a side-chain functionalized polythiophene is reported. …