A thermodynamics model for the emergence of a stripe-like binary SAM on a nanoparticle surface

Xinwei Ge, Pu Chun Ke, Thomas P Davis, Feng Ding

Research output: Contribution to journalArticleResearchpeer-review

17 Citations (Scopus)


It has been under debate if a self-assembled monolayer (SAM) with two immiscible ligands of different chain lengths and/or bulkiness can form a stripe-like pattern on a nanoparticle (NP) surface. The entropic gain upon such pattern formation due to difference in chain lengths and/or bulkiness has been proposed as the driving force in literature. Using atomistic discrete molecular dynamics simulations it is shown that stripe-like pattern could indeed emerge, but only for a subset of binary SAM systems. In addition to entropic contributions, the formation of a striped pattern also strongly depends upon interligand interactions governed by the physicochemical properties of the ligand constituents. Due to the interplay between entropy and enthalpy, a binary SAM system can be categorized into three different types depending on whether and under what condition a striped pattern can emerge. The results help clarify the ongoing debate and our proposed principle can aid in the engineering of novel binary SAMs on a NP surface. Free energy of different ligand distribution states on a nanoparticle surface as a function of temperature. Due to differences in relative potential energies, a binary self-assembled monolayer system can be categorized into three different types based on available equilibrium states from low to high temperatures.
Original languageEnglish
Pages (from-to)4894-4899
Number of pages6
Issue number37
Publication statusPublished - 2015


  • molecular dynamics
  • nanotechnology
  • self-assembled monolayers
  • self-assembly
  • striped nanoparticles

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