Materials Science

Localization of Spiropyran Activation


Functionalization of planar and curved glass surfaces with spiropyran (SP) molecules and localized UV-induced activation of the mechanophore are demonstrated. Fluorescence spectra of UV-irradiated SP-functionalized surfaces reveal that increases in surface roughness or curvature produces more efficient conversion of the mechanophore to the open merocyanine (MC) form. Further, force-induced activation of the mechanophore is achieved at curved glass-polymer interfaces and not planar interfaces. Minimal fluorescence signal from UV-irradiated SP-functionalized planar glass surfaces precluded mechanical activation testing. Curved glass-polymer interfaces are prepared by SP functionalization of E-glass fibers, which are subsequently embedded in a poly(methyl methacrylate) (PMMA) matrix. Mechanical activation is induced through shear loading by a single fiber microbond testing protocol. In situ detection of SP activation at the interface is monitored by fluorescence spectroscopy.


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Supplementary material

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SI ACS applmatinter