Premium
Mechanical behavior of a pH‐sensitive hydrogel ring used in a micro‐optical device
Author(s) -
Zalachas Nicolas,
Cai Shengqiang,
Suo Zhigang,
Lapusta Yuri
Publication year - 2012
Publication title -
pamm
Language(s) - English
Resource type - Journals
ISSN - 1617-7061
DOI - 10.1002/pamm.201210194
Subject(s) - swelling , self healing hydrogels , microlens , materials science , microsystem , polymer , rigidity (electromagnetism) , instability , swell , bridging (networking) , composite material , deformation (meteorology) , finite element method , nanotechnology , optics , lens (geology) , computer science , mechanics , polymer chemistry , physics , thermodynamics , computer network
A hydrogel is a polymer network that can absorb a large quantity of solvent and swell due to a physical or chemical stimulus. Hydrogels are more and more used as smart materials in recent micro‐applications. This fact requires the development of adequate models and simulation tools for their large deformation behavior. These models must also predict the onset of instabilities, such as folding or creasing. In this work, we study an interesting application of adaptive optical microsystem using a previously developed theory of inhomogeneous large deformation of a pH‐sensitive hydrogel. The devices function is based on the swelling of a ring made of a pH‐sensitive hydrogel. The latter controls the focal length of the liquid microlens. Our aim is to analyze major design parameters that affect the hydrogel ring behavior and the function of the micro‐optical device. The problem is solved numerically with the finite element commercial software ABAQUS. Various modes of large deformation and the influence of the rings aspect ratio on the behavior of the micro‐device are investigated. Results show that, for relatively short rings, a stable swelling takes place. Rings with a relatively big aspect ratio can have an unstable swelling with the propagation of a creasing instability. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)