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Title: Shape-tunable non-sinusoidal periodic structures fabricated via asymmetric thin film wrinkling

Abstract

Wrinkling of supported thin films is a buckling-based scalable and affordable technique for fabrication of periodic micro and nano scale structures over large areas. It has been used in the past to fabricate stretch-tunable functional structures for a variety of applications such as for optical gratings and microfluidics. Unfortunately, stretch-tunability in such structures is limited to only size and/or morphology tunability; the sinusoidal shape of the elementary wrinkled features cannot be tuned. Herein, we present a fabrication technique that overcomes this limitation by deterministically introducing asymmetry into the geometry of the thin film. Asymmetry was introduced by directional thin film deposition through a shadow mask. This shadow mask is generated in-situ through the self-shadowing effect of sinusoidal wrinkles that are themselves generated by partial release of stretch in a pre-stretched bilayer. After directional deposition, non-sinusoidal wrinkles were generated by further releasing the prestretch in the base layer. Here, we have (i) demonstrated the fabrication of non-sinusoidal wrinkles in polydimethylsiloxane/gold multilayers and (ii) computationally quantified the achievable asymmetry, i.e., the ratio of slopes on the two sides of the wrinkle peaks. We observe that the ratio of slopes can be increased to as much as 1.5 by increasing the thickness ofmore » the shadowdeposited film. Thus, our technique eliminates a major limitation of wrinkle-based devices and enables the use of wrinkled structures as shape-tunable features for applications such as tunable optics and stimuli-responsive materials.« less

Authors:
 [1];  [1]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Engineering Directorate
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA); USDOE Laboratory Directed Research and Development (LDRD) Program
OSTI Identifier:
1465292
Report Number(s):
LLNL-TR-754681
940172
DOE Contract Number:  
AC52-07NA27344; 15-FS-013
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 42 ENGINEERING; buckling; stretchable structures; flexible structures; shadow deposition; directional deposition

Citation Formats

Saha, Sourabh K., and Krauter, Kerry G. Shape-tunable non-sinusoidal periodic structures fabricated via asymmetric thin film wrinkling. United States: N. p., 2018. Web. doi:10.2172/1465292.
Saha, Sourabh K., & Krauter, Kerry G. Shape-tunable non-sinusoidal periodic structures fabricated via asymmetric thin film wrinkling. United States. doi:10.2172/1465292.
Saha, Sourabh K., and Krauter, Kerry G. Thu . "Shape-tunable non-sinusoidal periodic structures fabricated via asymmetric thin film wrinkling". United States. doi:10.2172/1465292. https://www.osti.gov/servlets/purl/1465292.
@article{osti_1465292,
title = {Shape-tunable non-sinusoidal periodic structures fabricated via asymmetric thin film wrinkling},
author = {Saha, Sourabh K. and Krauter, Kerry G.},
abstractNote = {Wrinkling of supported thin films is a buckling-based scalable and affordable technique for fabrication of periodic micro and nano scale structures over large areas. It has been used in the past to fabricate stretch-tunable functional structures for a variety of applications such as for optical gratings and microfluidics. Unfortunately, stretch-tunability in such structures is limited to only size and/or morphology tunability; the sinusoidal shape of the elementary wrinkled features cannot be tuned. Herein, we present a fabrication technique that overcomes this limitation by deterministically introducing asymmetry into the geometry of the thin film. Asymmetry was introduced by directional thin film deposition through a shadow mask. This shadow mask is generated in-situ through the self-shadowing effect of sinusoidal wrinkles that are themselves generated by partial release of stretch in a pre-stretched bilayer. After directional deposition, non-sinusoidal wrinkles were generated by further releasing the prestretch in the base layer. Here, we have (i) demonstrated the fabrication of non-sinusoidal wrinkles in polydimethylsiloxane/gold multilayers and (ii) computationally quantified the achievable asymmetry, i.e., the ratio of slopes on the two sides of the wrinkle peaks. We observe that the ratio of slopes can be increased to as much as 1.5 by increasing the thickness of the shadowdeposited film. Thus, our technique eliminates a major limitation of wrinkle-based devices and enables the use of wrinkled structures as shape-tunable features for applications such as tunable optics and stimuli-responsive materials.},
doi = {10.2172/1465292},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2018},
month = {7}
}