title: Integration of Triboluminescent EuD4TEA Crystals to Transparent Polymers: Impact Sensor Application.
abstract: Lanthanide-based organometallic materials are well-known candidate triboluminescent (TL) materials that can show bright emission when a mechanical force is applied. These materials are usually in the form of crystalline powders, and it is often useful to integrate these samples into a polymer matrix in order to achieve processability, enabling coating from a solution/molten state or fabrication as a complex-shaped matrix. In this work, micrometer-sized europium tetrakis (dibenzoylmethide) triethylammonium (EuD4TEA) crystals were synthesized and integrated with various transparent polymers (PMMA, PS, PVDF, and PU) using two approaches: (i) blending and (ii) surface impregnation. In the former method, the crystalline particles were molecularly dissolved; therefore, a TL response cannot be achieved. More than 10 wt % TL crystals in the composite is needed to obtain TL signals. However, TL signal was achieved at 2.5 wt % when a composite was prepared by the latter approach. TL intensity shows exponential decay with consecutive mechanical action. The TL emission of PU-based surface impregnated composite expires with long-lived emission, and maximum TL response with respect to applied force was measured between 2.45 and 42.0 N.
authors.forename: Anıl
authors.initials: A
authors.lastname: İncel
authors.forename: Mehtap
authors.initials: M
authors.lastname: Emirdag-Eanes
authors.affiliation: Department of Chemistry, Clemson University , 219 Hunter Laboratories, Clemson, South Carolina 29634, United States.
authors.forename: Colin D
authors.identifier: http://orcid.org/0000-0002-7773-8797
authors.initials: CD
authors.lastname: McMillen
authors.forename: Mustafa M
authors.identifier: http://orcid.org/0000-0003-1309-3990
authors.initials: MM
authors.lastname: Demir
keywords: blending; optical composites; piezoelectricity; single-crystal X-ray diffraction; surface impregnation; triboluminescence