Imbibition and dewetting of silica colloidal crystals: An NMR relaxometry study
| Autor: | Cefe López, Ioan Ardelean, Francisco Gallego-Gómez, Calin Cadar |
|---|---|
| Přispěvatelé: | Ministerio de Economía y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), Gallego-Gómez, Francisco [000-0001-9888-2889], López, Cefe [0000-0001-5635-4463], Gallego-Gómez, Francisco, López, Cefe |
| Rok vydání: | 2020 |
| Předmět: |
Void (astronomy)
Materials science 02 engineering and technology 010402 general chemistry 01 natural sciences Biomaterials Colloid Saturated and partially saturated media Colloid and Surface Chemistry Water-solid interface Silic a surface hydroxylation Stöber colloidal spheres Bound water Dewetting Silica colloidal crystals Relaxation (NMR) Colloidal crystal 021001 nanoscience & nanotechnology 0104 chemical sciences Surfaces Coatings and Films Electronic Optical and Magnetic Materials Wet particulate materials Chemical engineering Imbibition of porous media Imbibition Wetting and dewetting Wetting 0210 nano-technology low-field NMR relaxometry |
| Zdroj: | Digital.CSIC. Repositorio Institucional del CSIC instname |
| Popis: | [EN] Hypothesis: The wettability of the inner surfaces in a porous network is challenging to be accessed but essential to understand the complex performance of e.g. particulate systems. Experiments: Here we investigate the water behavior in the macroporous (50–100 nm) voids of dense particle packings by performing low-field H NMR relaxometry in solid silica colloid crystals. The systems chosen guarantee a regular, known void size distribution with controllable water affinity (through thermal annealing), where the NMR experiment clearly discriminates the void water from micropore or bound water contributions, allowing separate monitoring. Findings: Analysis of the saturated state indicates that the interparticle voids are completely filled after imbibition, even for less hydrophilic spheres. Due to the interaction with the silica surface, proton relaxation in void water is up to 100 times faster than that in bulk water, serving for assessment of the hydrophilicity within the sample. The relaxation time evolution upon dewetting provides an empirical measurement of the wettability inside the ensemble, revealing a progressively inhomogeneous wetting of increasingly hydrophobic surfaces. Our results provide insight into the imbibition state and dewetting performance in meso- and macroporous systems, with emphasis in the marked influence of the surface nature on the pore wetting distribution. This work was supported by the Spanish MINECO project MAT2014- 58731-JIN and MCIU grant RTI2018-093921-B-C41. I. A. acknowledges the partial support of the project 21 PFE in the frame of the program PDIPFE- CDI 2018. |
| Databáze: | OpenAIRE |
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