Immobilizing a Fluorescent Dye Offers Potential to Investigate the Glass/Resin Interface

• Published in: Journal of colloid and interface science Vol. 221; no. 1; pp. 75 - 86
• Main Authors: Lenhart, Joseph L., van Zanten, John H., Dunkers, Joy P., Zimba, Carl G., James, Calvin A., Pollack, Steven K., Parnas, Richard S.
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 01.01.2000; Elsevier
• Subjects: Applied sciences; coupling agent; dye; Exact sciences and technology; fluorescence; interface; Polymer industry, paints, wood; Properties and testing; sensor; Technology of polymers; Testing and control; dye; sensor; coupling agent; interface; fluorescence; Fluorescent tracer; Fiber reinforced material; Epoxy resin; Organic silane; Experimental study; Adhesion; Grafting; Composite material; Stilbene derivatives; Thermosetting resin; Coupling agent; Interface structure; Curing(plastics); Surface properties; Structure modification; Measurement method; Glass fiber; Modified material
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1006/jcis.1999.6577

Silane coupling agents are commonly applied to glass fibers to promote fiber/resin adhesion and enhance durability in composite parts. In this study, a coupling agent multilayer on glass was doped with trace levels of the dimethylaminonitrostilbene (DMANS) fluorophore. The fluorophore was immobilized on the glass surface by tethering the molecule to a triethoxy silane coupling agent, creating the DMANS/silane coupling agent molecule (DMSCA). DMSCA was then diluted with commonly used coupling agents and grafted to a glass microscope coverslip to create a model composite interface. A 53-nm blue shift in fluorescence from the immobilized DMSCA can be followed during cure of an epoxy resin overlayer, giving this technique potential to monitor the properties of the fiber/resin interface during composite processing. Contact angle measurements on these coupling agent layers were similar in the presence or absence of the DMSCA molecule, suggesting that trace levels of the fluorescent probe did not affect the structure of the layer. The immobilized DMSCA molecule behaved similarly to the DMANS precursor in solution. Both showed longer wavelength fluorescence in more polar environments.