New Method in Surface Treatment of Nanopipette for Interface between Two Immiscible Electrolyte Solutions (ITIES) Experiment
Interface between two immiscible electrolyte solutions (ITIES) is a powerful platform for chemical sensing and studying electron/ion transfer reactions and is typically formed between the interface of two immiscible solutions such as an oil phase and an aqueous phase. Micro/nano ITIES interface are generally formed at the tip of a borosilicate/quartz pipette, inner surface of which can be rendered hydrophobic to be filled with an organic solvent by a method called silanization. Nano/micrometer-sized electrodes are typically silanized by vapor silanization methods in which silanizing agent in vapor phase is exposed to nanopipettes. Micrometer-sized pipettes have been also silanized by directly filling liquid silanization agent, one type of liquid silanization methods, but this method has not been used at the nanoscale. Liquid silanization method allows to selectively silanize a single channel in a dual-channel pipette platform. Here, we developed the liquid silanization method for nanoscale ITIES and demonstrated that a stable cyclic voltammogram for tetrabutylammonium ion transfer across water/dichloroethane interface can be accomplished. We also presented challenges for liquid silanization at the nanoscale and strategies to overcome them. The liquid silanization methods presented here lay the foundation for future development of dual channel multi-functional probe where one channel is nanoITIES.
more »
« less
- Award ID(s):
- 1945274
- PAR ID:
- 10383821
- Date Published:
- Journal Name:
- Journal of The Electrochemical Society
- Volume:
- 169
- Issue:
- 4
- ISSN:
- 0013-4651
- Page Range / eLocation ID:
- 046501
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
Abstract Mesoscale chiral materials are prepared by lithographic methods, assembly of chiral building blocks, and through syntheses in the presence of polarized light. Typically, these processes result in micrometer‐sized structures, require complex top–down manipulation, or rely on tedious asymmetric separation. Chemical vapor deposition (CVD) polymerization of chiral precursors into supported films of liquid crystals (LCs) are discovered to result in superhierarchical arrangements of enantiomorphically pure nanofibers. Depending on the molecular chirality of the 1‐hydroxyethyl [2.2]paracyclophane precursor, extended arrays of enantiomorphic nanohelices are formed from achiral nematic templates. Arrays of chiral nanohelices extend over hundreds of micrometers and consistently display enantiomorphic micropatterns. The pitch of individual nanohelices depends on the enantiomeric excess and the purity of the chiral precursor, consistent with the theoretical model of a doubly twisted LC director configuration. During CVD of chiral precursors into cholesteric LC films, aspects of molecular and mesoscale asymmetry combine constructively to form regularly twisted nanohelices. Enantiomorphic surfaces permit the tailoring of a wide range of functional properties, such as the asymmetric induction of weak chiral systems.more » « less
-
Low-cost and scalable superhydrophobic coating methods provide viable approaches for energy-efficient separation of immiscible liquid/liquid mixtures. A scalable photopolymerization method is developed to functionalize porous substrates with a hybrid coating of tetrapodal ZnO (T-ZnO) and polymethacrylate, which exhibits simultaneous superhydrophobicity and superoleophilicity. Here, T-ZnO serves dual purposes by (i) initiating radical photopolymerization during the fabrication process through a hole-mediated pathway and (ii) providing a hierarchical surface roughness to amplify wettability characteristics and suspend liquid droplets in the metastable Cassie—Baxter regime. Photopolymerization provides a means to finely control the conversion and spatial distribution of the formed polymer, whilst allowing for facile large-area fabrication and potential coating on heat-sensitive substrates. Coated stainless-steel meshes and filter papers with desired superhydrophobic/superoleophilic properties exhibit excellent performance in separating stratified oil/water, oil/ionic-liquid, and water/ionic-liquid mixtures as well as water-in-oil emulsions. The hybrid coating demonstrates desired mechanical robustness and chemical resistance for their long-term application in large-scale energy-efficient separation of immiscible liquid/liquid mixtures.more » « less
-
Abstract A surfactant-free oil-in-oil emulsion-templating method is presented for fabrication of monolithic polyimide aerogel foams using monomer systems that produce fast sol–gel transition. An aerogel foam is a high porosity (∼90%) material with coexisting meso- and macropores inherent to aerogels with externally introduced micrometer size open cells (macrovoids) that are reminiscent of foams. The macrovoids are introduced in polyimide sol using surfactant-free emulsion-templating of droplets of an immiscible liquid that are stabilized against coalescence by fast sol–gel transition. Three immiscible liquids – cyclohexane, n -heptane, and silicone oil – are considered in this work for surfactant-free emulsion-templating. The aerogel foam monoliths, recovered by supercritical drying, exhibit smaller size macrovoids when n -heptane and cyclohexane are used as emulsion-templating liquid, while the overall porosity and the bulk density show weak dependence on the emulsion-templating liquid.more » « less
-
Abstract Emulsions are widely used in many industrial applications, and the development of efficient techniques for synthesizing them is a subject of ongoing research. Vapor condensation is a promising method for energy‐efficient, high‐throughput production of monodisperse nanoscale emulsions. However, previous studies using this technique are limited to producing small volumes of water‐in‐oil dispersions. In this work, a new method for the continuous synthesis of nanoscale emulsions (water‐in‐oil and oil‐in‐water) is presented by condensing vapor on free‐flowing surfactant solutions. The viability of oil vaporization and condensation is demonstrated under mild heating/cooling using diverse esters, terpenes, aromatic hydrocarbons, and alkanes. By systematically investigating water vapor and oil vapor condensation dynamics on bulk liquid‐surfactant solutions, a rich diversity of outcomes, including floating films, nanoscale drops, and hexagonally packed microdrops is uncovered. It is demonstrated that surfactant concentration impacts oil spreading, self‐emulsification, and such behavior can aid in the emulsification of condensed oil drops. This work represents a critical step toward advancing the vapor condensation method's applications for emulsions and colloidal systems, with broad implications for various fields and the development of new emulsion‐based products and industrial processes.more » « less
An official website of the United States government

