Open Porosity and Pore Size Distribution of Mesoporous Silica Films Investigated by Positron Annihilation Lifetime Spectroscopy and Ellipsometric Porosimetry

Xiong, Bangyun; Li, Jingjing; He, Chunqing; Lai, Jiale; Liu, Xiangjia; Huang, Tao

doi:10.3390/ma14123371

Cited by 3 publications

(2 citation statements)

References 42 publications

(76 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Parts of the results of these PAS experiments have already been described by Wilski [32]. This technique was used successfully multiple times for the porosity measurement of thin films on a nanoscale level [33][34][35][36][37][38][39][40].…”

Section: Combined Approach Of Measuring and Simulating Nanoscale Poresmentioning

confidence: 99%

Consideration of the effect of nanoscale porosity on mass transport phenomena in PECVD coatings

Franke,

Zysk,

Wilski

et al. 2024

J. Phys. D: Appl. Phys.

View full text Add to dashboard Cite

Here we show a novel approach to characterise the gas transfer behaviour of silicon-oxide (SiOx) coatings and explain the underlying dynamics. For this, we investigate the coating on a nm-scale both by measurement and simulation. Positron Annihilation Spectroscopy (PAS) and quantum mechanical electronic structure-based molecular dynamics simulations are combined to characterise the porous landscape of SiOx coatings. This approach analyses the influence of micropores smaller than 2 nm in diameter on gas permeation which are difficult to study with conventional methods. We lay out the main pore diameter ranges and their associated porosity estimates. An influence of layer growth on pore size and porosity was found, with an increased energy input during layer deposition leading to smaller pore sizes and a reduced porosity. The molecular dynamics simulations quantify the self-diffusion of oxygen and water vapor through those PAS deducted micropore ranges for hydrophilic and hydrophobic systems. The theoretical pore size ranges are fitting to our PAS results and complete them by giving diffusion coefficients. This approach enables detailed analysis of pore morphology on mass transport through thin film coatings and characterization of their barrier or membrane performance. This is a crucial prerequisite for the development of an exhaustive model of pore dominated mass transports in PECVD coatings.

show abstract

Section: Combined Approach Of Measuring and Simulating Nanoscale Poresmentioning

confidence: 99%

Consideration of the effect of nanoscale porosity on mass transport phenomena in PECVD coatings

Franke,

Zysk,

Wilski

et al. 2024

J. Phys. D: Appl. Phys.

View full text Add to dashboard Cite

show abstract

“…Mesoporous materials have been widely studied and applied in catalysis for their unique long-range ordered hexagonal symmetric channel structure and large surface area. [26][27][28][29][30] Herein, by reacting with APS and then nine substituted aromatic aldehydes, MCM materials were chemically modified with nine functional groups as the supports of Pd 2+ cations. The functional groups on the MCM-41 were confirmed by FT-IR spectra (Figures 1, S1, and S2).…”

Section: Characterization Of Supported Palladium Catalystsmentioning

confidence: 99%

Study on the relationship of catalytic activities and o‐Ps annihilation properties of supported palladium species chelated by different functional groups

Shao

et al. 2023

Applied Organom Chemis

View full text Add to dashboard Cite

A series of Schiff‐base functional groups modified MCM‐41 materials have been synthesized and used as the supports of palladium species. The chemical structures of MCM‐41 functionalized by nine Schiff‐base functional groups were characterized by Fourier transform infrared spectroscopy (FT‐IR), whereas their grafting densities of functional groups were achieved from the results of thermogravimetric analysis (TGA) and elemental analysis (EA). Small angle powdered X‐ray (SAX) patterns demonstrate that the ordered mesoporous structures of MCM‐41 were well retained after modification of functional groups and immobilization of Pd2+ cations. Moreover, the regular mesoporous structures of supports and homogeneous dispersions of Pd2+ cations were characterized by transmission electron microscopy (TEM). The positron annihilation lifetime spectroscopic (PALS) results revealed that the electronic and steric factors of functional groups could affect the o‐Ps annihilation properties of support Pd2+ cations. Meanwhile, the catalytic activities of these supported Pd2+ cations chelated by different functional groups were determined by the Heck reaction of iodobenzene with n‐butyl acrylate. At last, the catalytic activities of these supported Pd2+ cations were linearly correlated to their o‐Ps annihilation properties. This result demonstrates that the catalytic activities of supported Pd2+ cations chelated by different functional groups can be readily determined by the o‐Ps annihilation, which can be potentially used in the design and preparation of highly active palladium catalysts.

show abstract

Probing the influence of temperature on defects in oxy-hydroxide ceramics by positron annihilation lifetime and coincidence Doppler broadening spectroscopy

Ghasemifard

Ghamari

2022

Appl. Phys. A

View full text Add to dashboard Cite

Open Porosity and Pore Size Distribution of Mesoporous Silica Films Investigated by Positron Annihilation Lifetime Spectroscopy and Ellipsometric Porosimetry

Cited by 3 publications

References 42 publications

Consideration of the effect of nanoscale porosity on mass transport phenomena in PECVD coatings

Consideration of the effect of nanoscale porosity on mass transport phenomena in PECVD coatings

Study on the relationship of catalytic activities and o‐Ps annihilation properties of supported palladium species chelated by different functional groups

Probing the influence of temperature on defects in oxy-hydroxide ceramics by positron annihilation lifetime and coincidence Doppler broadening spectroscopy

Contact Info

Product

Resources

About