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Title: Strain and morphology of graphene membranes on responsive microhydrogel patterns

We study the configuration of atomically-thin graphene membranes on tunable microhydrogel patterns. The polyethylene oxide microhydrogel structures patterned by electron-beam lithography show increase in height, with a persistent swelling ratio up to ∼10, upon exposure to vapors of an organic solvent. We demonstrate that modifying the height fluctuations of the microhydrogel affects the strain and morphology of ultrathin graphene membrane over-layer. Raman spectroscopic investigations indicate that small lattice strains can be switched on in mechanically exfoliated few-layer graphene membranes that span these microhydrogel structures. In case of chemical-vapor deposited single-layer graphene, we observe Raman signatures of local depinning of the membranes upon swelling of microhydrogel pillars. We attribute this depinning transition to the competition between membrane-substrate adhesion energy and membrane strain energy, where the latter is tuned by hydrogel swelling.
Authors:
;  [1]
  1. Department of Physics, Indian Institute of Technology Madras, Chennai 600036 (India)
Publication Date:
OSTI Identifier:
22391967
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 19; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CHEMICAL VAPOR DEPOSITION; ELECTRON BEAMS; GRAPHENE; LAYERS; MEMBRANES; MORPHOLOGY; ORGANIC SOLVENTS; POLYETHYLENE GLYCOLS; STRAINS; SUBSTRATES; SWELLING