Other Chemistry Commons^™

Photothermally Induced Optical Property Changes Of Poly (N-Isopropylacrylamide) Microgel-Based Etalons, Molla R. Islam, Jessica Irvine, Michael J. Serpe

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Poly(N-isopropylacrylamide) microgel-based optical devices were designed such that they can be stimulated to change their optical properties in response to light produced by a light-emitting diode (LED). The devices were fabricated by sandwiching the synthesized microgels between two Cr/Au layers all supported on a glass coverslip with gold nanoparticles (AuNPs) deposited. Here, we found that these devices can be stimulated to change their optical properties when exposed to green LED light, which excites the AuNPs and increases the local temperature, causing the thermoresponsive microgels to decrease in diameter, resulting in a change in the devices’ optical properties. We also found …

Forensic Significance Of Teal Colored Cashmere And Black Acrylic Fibers, Nicole M. Martin

Forensic Science Theses

Textile fibers are a valuable type of trace evidence within forensic cases. They have the ability to connect a perpetrator to a victim and or a crime scene. Some types of fibers are more prevalent than others. The purpose of this research was to conduct a target fiber study in order to determine the significance of the selected fibers in a forensic case. Two fibers were selected from two different garments, black acrylic fiber and a teal colored cashmere fiber. Unknown fibers were collected from three local clothing stores and counted. Using light microscopy, all 20,164 fibers were eliminated as …

Investigation Of The Chemical Protection Capacity Of Common Shoe Materials In Undergraduate Laboratories, Sarah E. Lawson

Undergraduate Honors Theses

The objective of this study was to evaluate the chemical resistance of common shoe materials regularly worn in undergraduate chemistry laboratories by subjecting the materials to hydrochloric acid and sodium hydroxide. The materials tested were leather, canvas cotton, and polyester. Due to the lack of restriction on undergraduate laboratory footwear, the research discussed in this thesis is important to undergraduate universities. Currently, many universities across the nation only require undergraduate students to wear close-toed, close-heeled shoes in chemistry laboratories, and often the resistance of the shoe material to acids and bases may not be taken into careful consideration. Overall, the …

Green Chemistry As A Tool For Understanding The Toxic Substances Control Act: A Lecture Module For Undergraduate Students, Molly R. Blessing

Honors Scholar Theses

The Toxic Substances Control Act (TSCA) is the central form of chemical regulation existent in the United States today, yet scientists are often unaware or uncertain of its provisions. Violations of TSCA by unknowing chemists set industry and government unnecessarily at odds. A lecture on TSCA was developed for undergraduate students that uses the concept of green chemistry to promote interest and incentivize learning. Green chemistry methods are cleaner and less wasteful than traditional chemical ones, and many companies using them are at the forefront of technological innovation. The lecture explains both green chemistry and TSCA, includes company case studies, …

Bio-Crosslinking Of Starch Films With Oxidized Sucrose, Hazal Canisag

Department of Textiles, Merchandising and Fashion Design: Dissertations, Theses, and Student Research

In this work, corn starch films were crosslinked with a novel bio-based agent; oxidized sucrose and their strength and stability were improved. Although starch is an inexpensive, biodegradable and abundant source, industrial applications of starch films are limited due to their poor mechanical properties. Crosslinking is one of the most common methods to enhance the mechanical properties of starch films. However, most of the available crosslinkers, such as gluteraldehyde, phosphorus oxychloride, sodium trimetaphosphate, and epichlorohydrin, are either toxic, expensive or with low crosslinking efficiencies. Oxidized sucrose, which is derived by periodate cleavage, has aldehyde groups in the structure and this …

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.

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. …

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 …

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.

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.

Poly (N-Isopropylacrylamide) Microgel-Based Etalons And Etalon Arrays For Determining The Molecular Weight Of Polymers In Solution, Molla R. Islam, Michael J. Serpe

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Positively and/or negatively charged poly (N-isopropylacrylamide)-based microgels were deposited on a single substrate and isolated regions of Au overlayers were deposited on top of the microgels. Each spatially isolated Au overlayer region had a different thickness to make an etalon array.We found that areas with a thin Au overlayer (5 nm) responded to a range of polymer molecular weights (MW), while areas with a thick overlayer (35 nm) can only respond to low molecular weight polyelectrolytes. By comparing the optical responses of the device’s individual array elements, a good approximation of the polyelectrolyteMWin solution can be made.

Label-Free Detection Of Low Protein Concentration In Solution Using A Novel Colorimetric Assay, Molla R. Islam, Michael J. Serpe

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Dual pH and temperature sensitive microgel-based etalons were fabricated by sandwiching a “monolithic” microgel layer between two semitransparent, Au layers. The devices exhibit visual color and multipeak reflectance spectra, both of which primarily depend on the distance between the Au surfaces mediated by the microgel diameter. We found that a polycationic polyelectrolyte can penetrate through the Au overlayer to interact with negatively charged microgel confined between Au overlayers. In this submission we report that biotinylated polycationic polymer can penetrate through the Au overlayer of a poly (N-isopropylacrylamide)-co-acrylic acid (pNIPAm-co-AAc) microgel-based etalon and cause the microgel layer to collapse. The collapse …

The Effects Of Color Concentrates On The Rheology Of Tint Bases, Doug James Herrick

Master's Theses

ABSTRACT

THE EFFECTS OF COLOR CONCENTRATES ON THE RHEOLOGY OF TINT BASES

Douglas James Herrick

Waterborne coatings are formulated with a number of different ingredients; water, latex polymers, pigments, surfactants, dispersants, defoamers, biocides, coalescing aids, and rheology modifiers or thickeners. Rheology modifiers are necessary in order to improve the physical properties of the coating before, during, and after application to a substrate. There are two kinds of rheology modifiers used in waterborne coatings; associative thickeners and non-associative thickeners. Coatings formulated with associative thickeners are quite sensitive to coating variations; the slightest change in the formulation has profound effects on the …