Year: 2026
Type: preprint
Abstract: Understanding heat transport across polymer-coated surfaces is important for thermal management and for the design of functional nanomaterials used in technological and biomedical applications. Here, we use nonequilibrium molecular dynamics simulations to investigate thermal transport across Au(111) surfaces coated with thiolateanchored poly(ethylene glycol) (PEG) self-assembled monolayers. By varying the terminal group among OH, NH2, NH + 3 , N(CH3) + 3 , and CH3, we determine how interfacial chemistry modifies the overall Kapitza resistance and the balance of the resistance among the Au–PEG interface, the PEG layer and the PEG–water interface. By resolving the unequal heat currents through the bare and coated sides of the simulation cell, we decompose the coated-side resistance into Au–PEG interfacial, PEG layer, and PEG–water interfacial contributions. The neutral polar and charged terminal groups exhibit similar total thermal resistances (4.2–4.7 K m2 GW−1), whereas the hydrophobic CH3 termination produces a marked increase to ∼ 7 K m2 GW−1, primarily because of the PEG–water interfacial resistance. The thermal transport trends are consistent with differences in interfacial hydration and polymer–water organization, whereas vibrational spectral overlap alone does not provide a sufficient descriptor across the complete terminal group series. Increasing the PEG chain length raises the resistance of the PEG layer, whereas the coverage dependence of the effective Au interfacial resistance is described by a parallel thermal circuit model that combines Au–water and Au–PEG heat transfer contributions. These results identify terminal group chemistry, PEG chain length, and surface coverage as molecular design variables for tuning the thermal resistance of polymer-coated solid–liquid interfaces.
Source: ChemRxiv
Institution: Imperial College London
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7221714113