Mechanical Strain Sensing in a SIS-Type Elastomer with Single Site Strain Probes Based on Carbazole
摘要:
Four fluorescent strain probes with one or two carbazole units placed in the middle of an elastomeric triblock of polystyrene -polyisoprene-polystyrene (SIS) have been prepared and their fluorescence behaviors investigated under strain. The probes were dissolved in commercial SIS type rubbers at low levels of 0.1 wt %. Films cast from this blend were subjected to tensile elongation while the fluorescence spectra were obtained. A rather large change from ca. 0.7 to 1.1 in the relative intensity at two wavelengths (I-350/I-370) was observed on elongations up to 400%. The spectroscopic change is strongest for small strain levels around 0-200% and leveled out above 300-400%. This is attributed to changes in the intensities of the vibronic bands of the substituted carbazole units rather than changes in molecular overlap of carbazole dimers.
Four fluorescent strain probes with one or two carbazole units placed in the middle of an elastomeric triblock of polystyrene -polyisoprene-polystyrene (SIS) have been prepared and their fluorescence behaviors investigated under strain. The probes were dissolved in commercial SIS type rubbers at low levels of 0.1 wt %. Films cast from this blend were subjected to tensile elongation while the fluorescence spectra were obtained. A rather large change from ca. 0.7 to 1.1 in the relative intensity at two wavelengths (I-350/I-370) was observed on elongations up to 400%. The spectroscopic change is strongest for small strain levels around 0-200% and leveled out above 300-400%. This is attributed to changes in the intensities of the vibronic bands of the substituted carbazole units rather than changes in molecular overlap of carbazole dimers.