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ABSTRACT Composite nanostructured foams consisting of a metallic shell deposited on a polymeric core were formed by plating copper via electroless deposition on electrospun polycaprolactone (PCL) fiber mats. The final structure consisted of 1000-nm scale PCL fibers coated with 100s of nm of copper, leading to final core-shell thicknesses on the order of 1000-3000 nm. The resulting open cell, core-shell foams had relative densities between 4 and 15 %. By controlling the composition of the adjuncts in the plating bath, particularly the composition of formaldehyde, the relative thickness of copper coating as the fiber diameter could be controlled. As-spun PCL mats had a nominal compressive modulus on the order of 0.1 MPa; adding a uniform metallic shell increased the modulus up to 2 MPa for sub-10 % relative density foams. A computational materials science analysis using density functional theory was used to explore the effects pre-treatment with Pd may have on the density of nuclei formed during electroless plating.
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Deformation behavior of core–shell nanowire structures with coherent and semi-coherent interfaces
The mechanical properties of core–shell bimetallic composite nanowires, forming the bases of nanoporous metallic foams, have been investigated and compared with pure metal nanowires using molecular dynamics simulations. In the current study, pure copper and gold nanowires under uniaxial loading were tested at room temperature and compared to composite nanowires of the same materials (core) with a nickel coating (shell). The core radius ranged from 1 to 15 nm, and the shell thickness ranged from 0.1 to 5 nm. The tension strain was performed along the [001] direction under room temperature. Both coherent and semi-coherent composite nanowires were studied, and the effect of coating layer thickness was investigated. The strengthening mechanisms of the core–shell structures due to the presence of the two different types of interfaces were investigated for various nickel thicknesses. The atomistic simulation results revealed that the addition of the nickel shell strengthens the structure when the layer thickness exceeds a critical value.
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- Award ID(s):
- 1634640
- PAR ID:
- 10114084
- Date Published:
- Journal Name:
- Journal of Materials Research
- Volume:
- 34
- Issue:
- 07
- ISSN:
- 0884-2914
- Page Range / eLocation ID:
- 1093 to 1102
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1557/jmr.2018.491
