Threshold Temperature Sensors with Tunable Properties

Crenshaw, Brent R.; Kunzelman, Jill; Sing, Charles E.; Ander, Christine; Weder, Christoph

doi:10.1002/macp.200600622

Cited by 59 publications

(81 citation statements)

References 56 publications

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“…Indeed, the slope of the curve with 5 wt% of DCM is first higher and then lower than the slope of the curve with 0.5 wt% of DCM, which evidences the presence of both types of aggregates. This observation is fully consistent with a systematic study of dye aggregation reported in [66]. In fact, to optimize the optical quality of the dye-doped PMMA layer, it is annealed at 120…”

Section: Appendix B: Fluorescence Anisotropysupporting

confidence: 89%

“…above the T g of PMMA. As reported in [66], this process "leads to irreversible phase separation and the formation of dye aggregates". In consequence, the fluorescence lifetimes were measured with slightly doped layers (0.5 wt%), and lead to 1.8 ns for DCM, 2.6 ns for RH640 and 1.5 ns for PM605, in consistence with measurements reported elsewhere [70].…”

Section: Appendix B: Fluorescence Anisotropymentioning

confidence: 85%

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Gain properties of dye-doped polymer thin films

et al. 2015

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Hybrid pumping appears as a promising compromise in order to reach the much coveted goal of an electrically pumped organic laser. In such configuration the organic material is optically pumped by an electrically pumped inorganic device on chip. This engineering solution requires therefore an optimization of the organic gain medium under optical pumping. Here, we report a detailed study of the gain features of dye-doped polymer thin films. In particular we introduce the gain efficiency K, in order to facilitate comparison between different materials and experimental conditions. The gain efficiency was measured with various setups (pump-probe amplification, variable stripe length method, laser thresholds) in order to study several factors which modify the actual gain of a layer, namely the confinement factor, the pump polarization, the molecular anisotropy, and the re-absorption. For instance, for a 600 nm thick 5 wt% DCM doped PMMA layer, the different experimental approaches give a consistent value K ≃ 80 cm.MW −1 . On the contrary, the usual model predicting the gain from the characteristics of the material leads to an overestimation by two orders of magnitude, which raises a serious problem in the design of actual devices. In this context, we demonstrate the feasibility to infer the gain efficiency from the laser threshold of well-calibrated devices. Besides, temporal measurements at the picosecond scale were carried out to support the analysis.

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Section: Appendix B: Fluorescence Anisotropysupporting

confidence: 89%

Section: Appendix B: Fluorescence Anisotropymentioning

confidence: 85%

Gain properties of dye-doped polymer thin films

et al. 2015

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“…The approach exploits the excimer-forming properties of chromophores such as cyano-substituted oligo(phenylene vinylene)s [7][8][9][10][11][12] (cyano-OPVs, Figure 1) and further relies on the stimulus-driven self-assembly or dispersion of nano-scale aggregates of these sensor dyes in a range of host polymers. We have shown that this general concept of stimulus-triggered dye (dis)assembly in polymer matrices allows for the design of a broad range of sensor materials, which are useful for the detection of temperature history, [13][14][15][16][17] exposure to chemicals, [18,19] and mechanical deformation, [20][21][22][23][24] as well as more complex combinations of stimuli, such as seen in shape-memory materials. [25] Others have adapted the concept and extended it to a range of dyes including cyano containing poly(phenylene ethynylenes), [26] perylenes, [27] CdS nanoparticles, [28] and bis(benzoxazolyl)stilbenes.…”

Section: Introductionmentioning

confidence: 99%

“…This approach yields timetemperature indicating materials that exhibit a pronounced fluorescence color change, whose kinetics follow a predictable, Arrhenius-type behavior. [14][15][16][17] For humidity sensors, a hygroscopic host polymer is chosen, which has a T g that is above the desired working temperature. [18] Moisture serves to plasticize the matrix thus lowering T g and providing the mobility to facilitate the aggregation process.…”

Section: Introductionmentioning

confidence: 99%

Luminescent Mechanochromic Sensors Based on Poly(vinylidene fluoride) and Excimer‐Forming p‐Phenylene Vinylene Dyes

Lott

Weder

2009

Macro Chemistry & Physics

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Cyano‐substituted excimer‐forming oligo(phenylene vinylene) dyes (cyano‐OPVs) with terminal alkyl tails of different length were blended with two fluorinated host polymers with similar chemical composition but differing crystallinity. These blends were used to fabricate luminogenic mechanochromic thin films, which change their emission color upon deformation. The alkyl tails affect the solubility of the chromophores in the polymer matrix and lead to different aggregation properties; this is of importance because the mechanochromic fluorescence color change of the blends is related to the self‐assembly of the excimer‐forming dye in the unperturbed polymer matrix, and the dispersion of the dye aggregates upon deformation. Besides the length of the solubilizing tails, the dye concentration has an important influence on the aggregate size, which is crucial to creating a mechanochromic response, since the dye aggregates must be small enough to be dispersed during the deformation process. In‐situ opto‐mechanical measurements have shown that the mechanochromic effect occurs primarily during plastic deformation and that the mechanically induced dispersion of the dye aggregates becomes more pronounced as the crystallinity of the matrix polymer increases.magnified image

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“…While the study did also not involve well-defined supramolecular assemblies, the results paved the way for subsequent work on mechanochromic polymers comprising assemblies of aggregachromic, excimer-forming cyano-substituted oligo(p-phenylene vinylene)s (cyano-OPVs, Figures 2-4). [39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54] Scanning confocal microscopy images of blend films of ultra-high-molecular-weight polyethylene and 10 -4 % w/w EHO-OPPE (Figure 1). a) As prepared film.…”

Section: π-π Interactionsmentioning

confidence: 99%