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Structure, Conformations, and Diffusion in PDMS/Silica Nanocomposites via Atomistic MD Simulations
Argyrios V Karatrantos1, Nigel Clarke2, Lyazid Bouhala1
1Materials Research and Technology, Luxembourg Institute of Science and Technology, 5, Avenue des Hauts-Fourneaux, L-4362 Esch-sur-Alzette, Luxembourg.
Macromolecules
|March 2, 2026
Summary
This study reveals how ionic and neutral poly-(dimethylsiloxane) (PDMS) chains behave near nanosilica surfaces. Ionic interactions and chain charge density significantly impact PDMS structure and dynamics, crucial for designing advanced nanocomposites.
Area of Science:
- Materials Science
- Polymer Science
- Nanotechnology
Background:
- Poly-(dimethylsiloxane) (PDMS)-silica nanocomposites offer advanced properties like mechanical strength and superhydrophobicity.
- Understanding the interface and interphase is key for designing novel nanocomposites.
Purpose of the Study:
- To explore the structure, conformations, and diffusion of neutral and ionic PDMS melts confined between nanosilica surfaces.
- To provide nanoscale insights into the interface and interphase behavior of PDMS-silica systems.
Main Methods:
- Atomistic molecular dynamics simulations were employed.
- Investigated effects of hydrogen bonding, ionic interactions, temperature, chain charge density, electrostatic strength, and charge localization.
Main Results:
- Chain charge density significantly alters PDMS structure near ionic surfaces; ionic chain-end PDMS shows largest dimensions, while 10% charge density causes contraction.
- Ionic functionalization decreases PDMS chain dynamics compared to van der Waals and hydrogen bonding interactions.
- Neutral short PDMS chains exhibit faster diffusion; neutral long or ionic PDMS chains show subdiffusive behavior. Charge localization strongly affects ionic PDMS structure and dynamics.
Conclusions:
- Ionic interactions and chain charge density are critical factors influencing PDMS behavior at the nanoscale.
- Temperature has a minimal effect on neutral PDMS chains, while charge localization significantly impacts ionic PDMS.
- Findings offer crucial insights for the targeted design of high-performance PDMS-silica nanocomposites.
