Molla R. Islam

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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(More)
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(More)
Stimuli-responsive polymers are capable of translating changes in their local environment to changes in their chemical and/or physical properties. This ability allows stimuli-responsive polymers to be used for a wide range of applications. In this review, we highlight the analytical applications of stimuli-responsive polymers that have been published over(More)
Poly (N-isopropylacrylamide) (pNIPAm)-based microgels undergo a transition from fully water swollen (solvated) to deswollen (desolvated) as the temperature of the water they are dissolved in is increased >32 °C. In this submission, we examine how the temperature of this transition, i.e., the volume phase transition temperature (VPTT), depends on the(More)
Poly (N-isopropylacrylamide)-co-acrylic acid (pNIPAm-co-AAc) microgels were "painted" on the Au electrode of a quartz crystal microbalance (QCM). Another Au layer (overlayer) was subsequently deposited on the microgel layer. This structure is known as a microgel-based etalon. These devices have been shown to exhibit optical properties (i.e., color) that(More)
Biotin modified polycationic polymers are capable of penetrating the Au overlayer of poly(N-isopropylacrylamide)-co-acrylic acid microgel-based etalons. Once penetrated, the polycations crosslink the polyanionic microgels, causing them to collapse, resulting in a concomitant blue shift of the spectral peaks in the reflectance spectrum. We show that the(More)
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.
Poly (N-isopropylacrylamide-co-N-(3-aminopropyl) methacrylamide hydrochloride) microgel-based optical devices (etalons) have been shown to change their optical properties in the presence of single-stranded DNA. We hypothesize that this is due to the negatively charged DNA penetrating through the Au overlayer of the etalon, resulting in cross-linking and(More)