Nanoconfinement Effects on Redox Probe Transport in Lipid Assemblies on and in Mesoporous Silica Thin Films

Zhou, Shanshan; Guilfoil, Emma Caroline; He, Yuxin; Nagpure, Suraj; Islam, Syed Z.; Khan, M. Arif; Rankin, Stephen E.; Knutson, Barbara L.

doi:10.1002/admi.201901787

Cited by 5 publications

(5 citation statements)

References 60 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…23,25,57 This line becomes shorter as the surface charge resistance becomes greater in the restricted frequency range of the EIS experiments. 57 For this reason, the uncertainty associated with the Warburg impedance values are significant (Tables S3 and S4) when the surface resistance is the dominant element. The double layer capacitor represented by CPE1 arises from the potential difference between the electrode surface and the electrolyte.…”

Section: ■ Results and Discussionmentioning

confidence: 93%

“…This is consistent with the orthogonally (vertically) oriented hexagonal close-packed (o-HCP) structure obtained from our previous studies using the same film synthesis method. 56,57 The d-spacing of 9.6 nm in a hexagonal geometry yields a pore center-to-center distance of 2/√3× d-spacing or 11.2 nm. According to Coquil et al study, the wall thickness of the P123-templated 2D hexagonal porous structure in silica was determined to be 3 to 5 nm.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…The straight line following this semicircle corresponds to Ws1, the Warburg impedance, representing the 1D semi-infinite diffusion of the redox probe in the bulk electrolyte phase. ,, This line becomes shorter as the surface charge resistance becomes greater in the restricted frequency range of the EIS experiments . For this reason, the uncertainty associated with the Warburg impedance values are significant (Tables S3 and S4) when the surface resistance is the dominant element.…”

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Nanoconfinement Effects on the Transport of Redox Probes in Ionic Liquid-Loaded Mesoporous Silica Thin Films

Khan

Drake

et al. 2022

Ind. Eng. Chem. Res.

Self Cite

View full text Add to dashboard Cite

The transport of two redox probes, 1,1′-ferrocenedimethanol (FDM, hydrophilic) and 1,1′-dioctadecyl-4,4′-bipyridinium dibromide (DBD, hydrophobic), through ionic liquidfilled and/or functionalized silica nanoporous thin films is compared as a function of pore size (2.5 and 8 nm diameter pores). Electrochemical impedance spectroscopy (EIS) was used to measure the permeability of these aqueous probes through the bare silica films and silica films with pores containing a physically confined ionic liquid (IL, 1-butyl-3-methylimidazolium hexafluorophosphate (Functionalization of the nanoporous thin films with an IL-like group provides a barrier to the hydrophilic redox probe (a 40-fold decrease in permeability relative to bare 2.5 nm porous silica films), with only a 50% corresponding decrease in the permeability of the hydrophobic probe. The selectivity to hydrophobic solutes suggested by the barrier properties of IL-functionalized silica is less pronounced in the films with the larger 8 nm pores. Physically confining an IL in the pores of both bare and IL-functionalized pores results in similar transport as the corresponding non-IL filled pores. The ability to tune solute transport through nanoconfined ILs using pore size and surface functionalization is critical to the design of composite thin films for IL-based separation and energy storage applications.

show abstract

Section: ■ Results and Discussionmentioning

confidence: 93%

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Nanoconfinement Effects on the Transport of Redox Probes in Ionic Liquid-Loaded Mesoporous Silica Thin Films

Khan

Drake

et al. 2022

Ind. Eng. Chem. Res.

Self Cite

View full text Add to dashboard Cite

show abstract

“…[ 21 ] For mesoporous thin film characterization, EIS is rarely used although theoretically, the same setup as for routinely used CV can be applied. Among the few examples of EIS for mesoporous film characterization, Knutson and co‐workers [ 22 ] used EIS to analyze lipid‐filled, and lipid enveloped silica thin films concerning the transport of redox probes through this pore confinement. The lipid‐filled films showed an almost four times higher permeability of a hydrophobic redox probe and a 16‐fold decreasing permeability for hydrophilic probes.…”

Section: Introductionmentioning

confidence: 99%

Influence of Wettability on the Impedance of Ion Transport Through Mesoporous Silica Films

Ochs

Khalil

Frömling

et al. 2021

Adv Materials Inter

View full text Add to dashboard Cite

Functionalized nanopores have attracted strong interest in different fields in which nanopore transport is essential. Detailed insights into mass transport through nanopores and its correlation to pore wall properties such as wettability are essential. The potential and challenges using electrochemical impedance spectroscopy (EIS) to analyze mass transport through mesoporous silica thin films with precisely adjusted wettability are discussed. The accessible area of the electrode, the charge transfer or film resistance and the diffusion coefficients of the redox probe [Ru(NH3)6]2+/3+ inside the mesopores are determined. The influence of experimental parameters such as silica film pre‐treatment is evaluated. Hydrophilic mesoporous films display comparable diffusion coefficients around 1*10–8 cm2 s–1 independently of the exact wettability. As expected, hydrophobic films do not exhibit transport due to water exclusion. The sample pre‐treatment strongly influences the transport characteristics. Incubation into aqueous KCl leads to a decrease in the resistance for all tested mesoporous films. This is ascribed to an increase in the silanol group concentration at the pore wall. Besides the insights into mass transport in mesoporous films and on how to measure EIS in such films, this study elucidates the importance of sample pre‐treatment and surface chemistry concerning mesoporous film performance.

show abstract

“…They were already used as support for lipid membranes, increasing their mechanical stability and leaving space under the membrane, for example, for transmembrane proteins. Lipid membranes could therefore be studied with characterization techniques such as AFM, quartz crystal balance, and electrochemical impedance spectroscopy (Claesson et al, 2010;Claesson et al, 2011;Zhou et al, 2020). Synthetic lipid bilayers are widely studied, as they can be employed to mimic cell membranes, making them very attractive in fields such as drug delivery and biosensing.…”

Section: Introductionmentioning

confidence: 99%

Structural Study of the Hydration of Lipid Membranes Upon Interaction With Mesoporous Supports Prepared by Standard Methods and/or X‐Ray Irradiation

et al. 2021

View full text Add to dashboard Cite

Mesoporous materials feature ordered tailored structures with uniform pore sizes and highly accessible surface areas, making them an ideal host for functional organic molecules or nanoparticles for analytical and sensing applications. Moreover, as their porosity could be employed to deliver fluids, they could be suitable materials for nanofluidic devices. As a first step in this direction, we present a study of the hydration of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) model lipid membranes on solid mesoporous support. POPC was selected as it changes the structure upon hydration at room temperature. Mesoporous films were prepared using two different templating agents, Pluronic P123 (PEO–PPO–PEO triblock copolymer where PEO is polyethylene oxide and PPO is polypropylene oxide) and Brij 58 (C16H33(EO)20OH where EO is ethylene oxide), both following the conventional route and by X-ray irradiation via deep X-ray lithography technique and subsequent development. The same samples were additionally functionalized with a self-assembly monolayer (SAM) of (3-aminopropyl)triethoxysilane. For every film, the contact angle was measured. A time resolved structural study was conducted using in situ grazing incidence small-angle X-ray scattering while increasing the external humidity (RH), from 15 to 75% in a specially designed chamber. The measurements evidenced that the lipid membrane hydration on mesoporous films occurs at a lower humidity value with respect to POPC deposited on silicon substrates, demonstrating the possibility of using porosity to convey water from below. A different level of hydration was reached by using the mesoporous thin film prepared with conventional methods or the irradiated ones, or by functionalizing the film using the SAM strategy, meaning that the hydration can be partially selectively tuned. Therefore, mesoporous films can be employed as “interactive” sample holders with specimens deposited on them. Moreover, thanks to the possibility of patterning the films using deep X-ray lithography, devices for biological studies of increasing complexity by selectively functionalizing the mesopores with biofunctional SAMs could be designed and fabricated.

show abstract

Nanoconfinement Effects on Redox Probe Transport in Lipid Assemblies on and in Mesoporous Silica Thin Films

Cited by 5 publications

References 60 publications

Nanoconfinement Effects on the Transport of Redox Probes in Ionic Liquid-Loaded Mesoporous Silica Thin Films

Nanoconfinement Effects on the Transport of Redox Probes in Ionic Liquid-Loaded Mesoporous Silica Thin Films

Influence of Wettability on the Impedance of Ion Transport Through Mesoporous Silica Films

Structural Study of the Hydration of Lipid Membranes Upon Interaction With Mesoporous Supports Prepared by Standard Methods and/or X‐Ray Irradiation

Contact Info

Product

Resources

About