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Title: Adhesion and Wetting of Soft Nanoparticles on Textured Surfaces: Transition between Wenzel and Cassie-Baxter States

In this paper, we use a combination of the molecular dynamics simulations and scaling analysis to study interactions between gel-like nanoparticles and substrates covered with rectangular shape posts. Our simulations have shown that nanoparticles in contact with substrate undergo a first-order transition between the Cassie–Baxter and Wenzel states, which depends on nanoparticle shear modulus, the strength of nanoparticle–substrate interactions, height of the substrate posts, and nanoparticle size, Rp. There is a range of system parameters where these two states coexist such that the average indentation δ produced by substrate posts changes with nanoparticle shear modulus, Gp. We have developed a scaling model that describes deformation of nanoparticle in contact with patterned substrate. In the framework of this model, the effect of the patterned substrate can be taken into account by introducing an effective work of adhesion, Weff, which describes the first-order transition between Wenzel and Cassie–Baxter states. There are two different shape deformation regimes for nanoparticles with shear modulus Gp and surface tension γp. The shape of small nanoparticles with size Rp < γp3/2Gp–1Weff–1/2 is controlled by capillary forces, while deformation of large nanoparticles, Rp > γp3/2Gp–1Weff–1/2, is determined by nanoparticle elastic and contact free energies. The model predictions aremore » in good agreement with simulation results.« less
Authors:
 [1] ;  [2] ;  [3] ;  [1]
  1. Univ. of Connecticut, Storrs, CT (United States). Polymer Program and Inst. of Materials Science
  2. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Center for integrated Nanotechnologies
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). National Center for Computational Science
Publication Date:
OSTI Identifier:
1185005
Report Number(s):
SAND-2014-20413J
Journal ID: ISSN 0743-7463; 547747
Grant/Contract Number:
AC04-94AL85000; AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Langmuir
Additional Journal Information:
Journal Volume: 31; Journal Issue: 5; Journal ID: ISSN 0743-7463
Publisher:
American Chemical Society
Research Org:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; 36 MATERIALS SCIENCE