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Davis CS, Rencheck ML, Woodcock JW, Beams R, Wang M, Stranick S, Forster AM, Gilman JW. Activation of Mechanophores in a Thermoset Matrix by Instrumented Scratch. ACS APPLIED MATERIALS & INTERFACES 2021; 13:55498-55506. [PMID: 34780164 DOI: 10.1021/acsami.1c15004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Scratches in polymer coatings and barrier layers negatively impact optical properties (haze, light transmission, etc.), initiate routes of degradation or corrosion (moisture permeability), and nucleate delamination of the coating. Detecting scratches in coatings on advanced materials systems is an important component of structural health monitoring but can be difficult if the defects are too small to be detected by the naked eye. The primary focus of the present work is to investigate scratch damage using fluorescence lifetime imaging microscopy (FLIM) and mechanical activation of a mechanophore (MP)-containing transparent epoxy coating. The approach utilizes a Berkovich tip to scratch MP-epoxy coatings under a linearly increasing normal load. The goal is to utilize the fluorescent behavior of activated MPs to enable the detection of microscale scratches and molecular scale changes in polymeric systems. Taking advantage of the amine functionality present in a polyetheramine/bisphenol A epoxy network, a modified rhodamine dye is covalently bonded into a transparent, thermoset polymer network. Following instrumented scratch application, subsequent fluorescence imaging of the scratched MP-epoxy reveals the extent of fluorescence activation induced by the mechanical deformation. In this work, the rhodamine-based mechanophore is used to identify both ductile and fracture-dominated processes during the scratch application. The fluorescence intensity increases linearly with the applied normal load and is sensitive to fracture dominated processes. Fluorescence lifetime and hyperspectral imaging of damage zones provide additional insight into the local (nanoscopic) environment and molecular structure of the MP around the fracture process zone, respectively. The mechanophore/scratch deformation approach allows a fluorescence microscope to probe local yielding and fracture events in a powerful way that enhances the optical characterization of damage zones formed by standard scratch test methods and leads to novel defect detection strategies.
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Affiliation(s)
- Chelsea S Davis
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-3460, United States
- School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907-2045, United States
| | - Mitchell L Rencheck
- School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907-2045, United States
| | - Jeremiah W Woodcock
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-3460, United States
| | - Ryan Beams
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-3460, United States
| | - Muzhou Wang
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-3460, United States
| | - Stephan Stranick
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-3460, United States
| | - Aaron M Forster
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-3460, United States
| | - Jeffrey W Gilman
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-3460, United States
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Gibson RF, Jang HK, Simkhada S, Yu Q, Kim HI, Suhr J. Use of Nanoindentation, Finite Element Simulations, and a Combined Experimental/Numerical Approach to Characterize Elastic Moduli of Individual Porous Silica Particles. PARTICULATE SCIENCE AND TECHNOLOGY 2015. [DOI: 10.1080/02726351.2014.950396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Hare BA, Sue HJ, Liang LY, Kinigakis P. Scratch behavior of extrusion and adhesive laminated multilayer food packaging films. POLYM ENG SCI 2013. [DOI: 10.1002/pen.23544] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Brian A. Hare
- Department of Mechanical Engineering; Polymer Technology Center; Texas A&M University; College Station Texas 77843-3123
| | - Hung-Jue Sue
- Department of Mechanical Engineering; Polymer Technology Center; Texas A&M University; College Station Texas 77843-3123
| | - Lora Ying Liang
- Kraft Foods Global Inc.; 801 Waukegan Road Glenview Illinois 60025
| | - Panos Kinigakis
- Kraft Foods Global Inc.; 801 Waukegan Road Glenview Illinois 60025
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