Solvent diffusion in polymer-embedded hollow nanoparticles studied by in situ small angle X-ray scattering

Area of Science:

• Materials Science
• Nanotechnology
• Physical Chemistry

Background:

• Ceramic hollow nanoparticles (HNPs) are crucial in advanced materials.
• Understanding solvent diffusion within nanomaterials is essential for their application.
• Polymer gel scaffolds offer unique environments for nanomaterial integration.

Purpose of the Study:

• To develop and validate a method for monitoring solvent diffusion in ceramic HNPs.
• To analyze the kinetics of solvent penetration into HNPs and polymer gels.
• To quantify diffusion coefficients and rate constants for solvent transport.

Main Methods:

• In situ time-resolved small-angle X-ray scattering (TR-SAXS).
• Analysis using discrete scattering models and a consecutive reaction kinetic model.
• Model system: diffusion of poly(ethylene glycol) in poly(ethylene oxide)-embedded HNPs.

Main Results:

• Successfully monitored solvent diffusion through ceramic HNPs and polymer gel scaffolds.
• Determined solvent penetration times: 0.7 s for HNP shell, 1.2 s for HNP cavity.
• Calculated diffusion coefficients on the order of 10^-18 m² s^-1.

Conclusions:

• TR-SAXS is effective for simultaneous measurement of solvent diffusion in gels and embedded HNPs.
• The method provides insights into nanoscale transport phenomena.
• This technique is valuable for characterizing nanomaterial-polymer composite systems.