Zhuang Wu, , , Masoumeh N. Salimi, , , Dean C. Webster, , , Andrew B. Croll, , and , Wenjie Xia*,
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引用次数: 0
Abstract
Silicone-based polymers, particularly polydimethylsiloxane (PDMS), are esteemed for their exceptional thermal stability, hydrophobicity, and biocompatibility. This study leverages atomistically informed coarse-grained molecular dynamics (CG-MD) simulations to explore the interfacial adhesive characteristics of PDMS films subjected to nanoindentation, with a focus on the influences of interfacial interaction strength between nanoindenter and polymer chains, temperature, and cross-link density, interpreted through the classic Johnson–Kendall–Roberts (JKR) model. Our findings reveal that increasing the interfacial interaction strength significantly enhances adhesion, necessitating a greater energy for separation. Notably, beyond a certain threshold, the adhesion exhibits a plateau, as quantified by the apparent critical energy release rate, Gc. This saturation in Gc can be attributed to chain adsorption on the indenter tip. Such an interfacial adsorption phenomenon becomes more pronounced at elevated temperatures along with a concomitant decrease in Gc, due to enhanced chain mobility. Additionally, increasing cross-link density of the PDMS network reduces chain adsorption during indentation, thereby resulting in a higher apparent Gc. Our simulation results, confirmed by the experimental Atomic Force Microscopy (AFM) measurements, offer valuable insights into interfacial behavior of silicone-based polymers, highlighting the intricate interplay among interaction strength, temperature, and cross-link density in quantifying adhesive properties of PDMS films.
期刊介绍：
Macromolecules publishes original, fundamental, and impactful research on all aspects of polymer science. Topics of interest include synthesis (e.g., controlled polymerizations, polymerization catalysis, post polymerization modification, new monomer structures and polymer architectures, and polymerization mechanisms/kinetics analysis); phase behavior, thermodynamics, dynamic, and ordering/disordering phenomena (e.g., self-assembly, gelation, crystallization, solution/melt/solid-state characteristics); structure and properties (e.g., mechanical and rheological properties, surface/interfacial characteristics, electronic and transport properties); new state of the art characterization (e.g., spectroscopy, scattering, microscopy, rheology), simulation (e.g., Monte Carlo, molecular dynamics, multi-scale/coarse-grained modeling), and theoretical methods. Renewable/sustainable polymers, polymer networks, responsive polymers, electro-, magneto- and opto-active macromolecules, inorganic polymers, charge-transporting polymers (ion-containing, semiconducting, and conducting), nanostructured polymers, and polymer composites are also of interest. Typical papers published in Macromolecules showcase important and innovative concepts, experimental methods/observations, and theoretical/computational approaches that demonstrate a fundamental advance in the understanding of polymers.
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