PMSE 83 |
| In coatings, wrinkles are viewed as defects, or as desired features for low gloss, and texture. In either case, discovering the origin of wrinkles and the conditions that lead to their formation is important. In this research wrinkling of a two-layer coating, comprised of a stiff elastic layer atop a complaint bottom layer, was studied. Wrinkles of 180-200 μm wavelength formed when the coating was exposed to humid atmosphere. The top layer of the coating develops in-plane compressive stress by absorbing moisture, and when the compressive stress is high enough, the top layer buckles to produce wrinkles. Experimental observations compared well with predictions from a model based on Flory-Rehner free energy and linear stability analysis. Linear stability analysis predicts that the compressed top layer is unstable to intermediate wavelengths of buckling; better solvent, higher ratio of bottom-to-top layer thickness, and lower bottom layer modulus produce higher wavelength, higher amplitude wrinkles. |
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Tess Award Symposium in Honor of L. E. (Skip) Scriven
8:00 AM-12:05 PM, Monday, August 20, 2007 Westin Boston Waterfront -- Grand Ballroom D, Oral
Division of Polymeric Materials: Science & Engineering |