Investigation of modified nanopore arrays using FIB/SEM tomography

Abstract

The investigation of electrochemical processes at the interface of two immiscible electrolyte solutions (ITIES) is of great interest for sensing applications, and serves as a surrogate to the study of biological transport phenomena, e.g. ion channels. Alongside e-beam lithography, focused ion beam (FIB) milling is an attractive method to prototype and fabricate nanopore arrays that support nanoITIES. Within this contribution, we explore the capability of FIB/scanning electron microscopy (SEM) tomography to visualize the actual pore structure and interfaces at silica-modified nanoporous membranes. The nanopores were also characterized by atomic force microscopy (AFM) using ultra-sharp AFM probes to determine the pore diameter, and using scanning transmission electron microscopy (STEM) and energy dispersive X-ray (EDX) spectroscopy, providing additional information on the elemental composition of deposits within the pores. Si-rich particles could be identified within the pores as well as at the orifice that had faced the organic electrolyte solution during electrochemical deposition. The prospects of the used techniques for investigating the interface at or within FIB-milled nanopores will be discussed.

Ion transfer at polarised liquid-liquid interfaces modified with adsorbed silica nanoparticles

“…The growing interest for the use of silica-based materials at the liquid-liquid interface is also due to their favourable adsorption kinetics and selectivity [28], which could be harnessed to the development of new sensing methods [29,30]. ITIES was modified by the electrogeneration of mesoporous silica deposits [31][32][33][34][35], which were the result of an electrochemically driven ion transfer followed by interfacial precipitation. Mesoporous silica was generated at the ITIES by the transfer of a cationic surfactant (e.g.…”

Advanced Materials for Energy-Water Systems: The Central Role of Water/Solid Interfaces in Adsorption, Reactivity, and Transport

“…SECM studies allow for the examination of a single pore or well-characterized membrane regions, − providing information for direct comparison with theory and simulations that seek to model transport on the atomic and nanoscales, the key length-scales that govern mass transport through such media Figure b illustrates the ability to locate and sample fluxes emanating from a single pore.…”

Heroin detection in a droplet hosted in a 3D printed support at the miniaturized electrified liquid-liquid interface

“…eLLI miniaturization has a few crucial benefits over traditional macroscopic counterparts: (i) minimal consumption of the chemicals; (ii) lower capacitive currents; (iii) higher mass transfer to eLLI and (iv) improved stability of the soft junction governed by the pre-adjusted microscopic aperture surface wettability 32 . Approaches used to miniaturize eLLI can be based on metal wire templated glass capillary 33 , pulled glass capillaries 30,34 , patterned glass slides 35 , laser-ablated polymeric films 36 , micro-punched films 28,37 , apertures fabricated in the SiN chips [38][39][40] , or simply are based on porous materials such as zeolites, mesoporous silica of fiberglass membranes [41][42][43][44] . Miniaturization protocols are also frequently applied during sample preparation aiming at e.g.…”