Ion-conducting polymers are important materials for a variety of electrochemical applications. Perfluorinated ionomers, such as Nafion, the benchmark proton conduction and widely used in fuel cells other devices including solar-fuel generators, chlor-alkali cells, redox flow batteries. While behavior Nafion bulk membranes (10 to 100s μm thick) has been studied extensively, understanding its properties under thin-film confinement is limited. Elucidating thin films particularly optimization...

Fluorescence of 9-(2-carboxy-2-cyanovinyl)julolidine (CCVJ) was measured to probe the local motion within 70-600 nm thick Nafion films at controlled levels hydration. Thinner showed increased confinement under dry conditions as evidenced by their high fluorescence intensity values per unit thickness. Antiplasticization, or a stiffening film, observed an increase in when sample exposed low water activity (≤30% RH) and extent antiplasticization changed with film At higher relative humidities,...

Steady-state fluorescence measurements of two different probe molecules were undertaken to explore the water solvation environment and molecular mobility in 70–600 nm NAFION thin films 50 μm thick membranes. The influence film thickness, hydration number, polymer–substrate interaction on proton dissociation transfer from photoexcited 8-hydroxypyrene-1,3,6-trisulfonic acid sodium salt (HPTS) surrounding local 9-(2-carboxy-2-cyanovinyl)julolidine (CCVJ) samples investigated. Deprotonation...

Virus filtration is used to ensure drug safety in the production of biotherapeutics. Several recent studies have shown a dramatic decrease virus retention as result process disruption, e.g., transient pressure release. In this work, novel two-label fluorescence technique was developed probe capture within membranes using confocal microscopy. Experiments were performed with Ultipor® DV20, Viresolve® Pro, and NFP bacteriophage φx174 model virus. The filters challenged two batches fluorescently...

Virus filtration can provide a robust method for removal of adventitious parvoviruses in the production biotherapeutics. Although virus is typically thought to function by purely size-based mechanism, there limited data literature indicating that retention solution conditions. The objective this work was examine effect pH and ionic strength on Viresolve(®) NFP membrane. Data were obtained using bacteriophage ϕX174 as model virus, with complemented use confocal microscopy directly visualize...

In this work, we utilized an inexpensive and naturally abundant polymer lignin functionalized it with quaternary ammonium groups to yield a cationic antimicrobial, QAL. As opposed non-cationic alkali (AL), relatively low concentration of QAL (∼25–150 μg/mL) exerted strong bacteriostatic bacteriolytic effects against both wild-type kanamycin (kan)-resistant E. coli (∼90% dead cells, ∼90–100% growth inhibition 1 h treatment). Treatment 25 μg/mL exposed lipid (Nile red staining) roughened the...

Abstract An in-depth understanding of cell-drug binding modes and action mechanisms can potentially guide the future design novel drugs antimicrobial materials help to combat antibiotic resistance. Light-harvesting π-conjugated molecules have been demonstrated for their effects, but impact on bacterial outer cell envelope needs be studied in detail. Here, we synthesized poly(phenylene) based model cationic conjugated oligo- (2QA-CCOE, 4QA-CCOE) polyelectrolytes (CCPE), systematically...

Unraveling ion conduction limitations in nanothin ionomer films is crucial for designing efficient ionomer–catalyst interfaces and improving redox efficiency electrochemical devices. This work took a multifaceted approach to understand local proton environments sub-μm thick of three fluorocarbon-based ionomers, Nafion, 3M PFSA PFIA with IEC ∼ 0.91, 1.21, 1.61 mequiv/g, respectively. After incorporating fluorescent photoacid probe pyranine (HPTS) into films, the extent (Id/Ip), concentration,...

Converting industrial/agricultural lignin-rich wastes to efficient, cost-effective materials for electrochemical devices (e.g. fuel cells) can aid in both bio- and energy economy. A major limitation of cells is the weak ion conductivity within ~2-30 nm thick, ion-conducting polymer (ionomer)-based catalyst-binder layer over electrodes. Here, we strategically sulfonated kraft lignin (a by-product pulp paper industries) design ionomers with varied exchange capacities (IECs) (LS x; x= IEC) that...

Cationic, π-conjugated oligo-/polyelectrolytes (CCOEs/CCPEs) have shown great potential as antimicrobial materials to fight against antibiotic resistance. In this work, we treated wild-type and ampicillin-resistant (amp-resistant) Escherichia coli (E. coli) with a promising cationic, polyelectrolyte (P1) phenylene-based backbone investigated the resulting morphological, mechanical, compositional changes of outer membrane bacteria in detail. The cationic quaternary amine groups P1 led...

The mechanical and transport properties of submicron thick ionomer films are crucial in the study understanding ionomer–catalyst interfaces porous electrodes energy conversion storage devices, such as fuel cells batteries. Interestingly, ionomers thin behave differently from bulk membranes, behavior these is not well understood. complex hydration confined state described this work. Here, (∼25–250 nm) sulfonated Radel (S-Radel) were investigated to understand thickness effects on density...

Sub-micrometer-thick ion-conducting polymer (ionomer) layers often suffer from poor ionic conductivity at the substrate/catalyst interface. The weak proton makes electrochemical reaction cathode of proton-exchange-membrane fuel cells sluggish. To address this, here we report on a class polystyrene-based ionomers having sub-nanometer-sized, sulfonated macrocyclic calix[4]arene-based pendants (PS-calix). In films with thickness comparable to that ionomer-based binder layers, PS-calix film (∼41...

A simple and efficient approach was developed for the synthesis of a series cationic water-soluble oligofluorenes up to chain length heptamer. Bromoalkyl-substituted fluorenyl boronic esters as key intermediates were synthesized by using modified Miyaura reaction. With an increasing number repeat units (trimer hexamer), size-specific oligomers have shown redshifts in both absorption emission maxima. The maximum reaches limit hexamer water buffer solution. quantum yields decreased with...

Poor ionic conductivity of the catalyst-binding, sub-micrometer-thick ionomer layers in energy conversion and storage devices is a huge challenge. However, ionomers are rarely designed keeping mind specific issues associated with nanoconfinement. Here, we nature-inspired (calix-2) having hollow, macrocyclic, calix[4]arene-based repeat units precise, sub-nanometer diameter. In ≤100 nm-thick films, in-plane proton calix-2 was up to 8 times higher than current benchmark Nafion at 85% relative...

Interfacial confinement-induced weak proton conduction in sub-μm-thick ionomer films impacts the performance of electrochemical devices. In such films, a fraction chains align parallel next to substrates. The ionomer–substrate interaction pins substrate, limiting conductivity across film. We addressed this interfacial chain-pinning and ion transport limitation by covalently immobilizing (3-aminopropyl)triethoxysilane (APTES) on SiO2 before depositing Nafion (∼60–700 nm thick) top it. silane...

We report a macromolecular end-capping approach to improve the detection sensitivity of cationic conjugated polymer (CCP) based DNA detection. A phenylethynyl anthracene (PEA) end-capped polyfluorene (PF) derivative (P1) is synthesized via Suzuki coupling. Due efficient fluorescence resonance energy transfer (FRET) from backbone end-capper PEA units, dominated by emission even in dilute aqueous solution. P1 has better spectral overlap with fluorescein (Fl) absorption compared that for...

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Interfacial behavior of submicron thick polymer films critically controls the performance electrochemical devices. We developed a robust, everyday-accessible, fluorescence confocal laser scanning microscopy (CLSM)-based strategy that can probe distribution mobility, ion conduction, and other properties across ionomer samples. When fluorescent photoacid 8-hydroxypyrene-1,3,6-trisulfonic acid trisodium salt (HPTS) was incorporated into <1 μm Nafion on substrates, depth-profile images showed...

This paper discusses the impact of COVID-19 pandemic on education and STEM learning, leading to development implementation a virtual camp.It highlights benefits camps in providing accessible inclusive learning experiences, breaking geographical barriers, promoting equity.The also proposes concept hybrid camp for middle high schoolers, combining advantages both inperson formats.Drawing from experiences Nanomaterials group, under guidance Professor Shudipto K. Dishari, at University...