Temperature and chemical environment effects on the aggregation extent of water soluble perylene dye into vinyl alcohol-containing polymers

Abstract

In this work, a water soluble perylene derivative containing piperazine peripheral units, i.e. N,N'-bis(2-(1-piperazino)ethyl)-3,4,9,10-perylenetetracarboxylic acid diimide dichloride (PZPER) was synthesized and dispersed at low loadings (from 0.1 to 1.1 wt%) into vinyl alcohol-containing polymer matrices. From the data acquired, the most effective driving force for the formation of intramolecular aggregates of PZPER was attributed to hydrogen bonding interactions. In particular, the aggregation extent was affected by the reduction of molecular interactions occurring in both solution and in polymer dispersions due to the decreasing polarity of the chromophore environment or increasing temperature. The sensitivity of PZPER aggregates dispersed into vinyl alcohol-containing polymer matrices towards mechanical stress was also reported. The responsiveness of PZPER optical properties (both in absorption and in emission) versus thermal or mechanical solicitations suggests applications of polymer dispersions as smart indicators to external stimuli.

MWCNT/perylene bisimide water dispersions for miniaturized temperature sensors

“…30 Researchers tried to identify structure-property relationships of perylene/CNT mixtures in order to provide innovative materials for nanostructured electronic devices and The ability of PZPER molecules to generate π−π stacking interactions has been previously utilized by our group for the preparation of chromogenic plastic materials as temperature indicators. 31 The effective π-associations between PZPERY and MWCNTs suggested to us that these nanocomposites should function as temperature sensors, since both semiconducting and metallic Cl resistance sensitivity of only -0.004 K -1 , a value which is comparable to that found in metals. 6,32,33 Such low sensitivity was ascribed to the polymeric dispersants, such as poly(styrene-b-(ethylene-cobutylene)-b-styrene) (SEBS) 6 or poly(vinylbenzyl chloride) derivative with triethylamine, 32 and the insulating nature of these components limit the thermal and electronic conductivities of the nanocomposite.…”

The unique optical behaviour of bio‐related materials with organic chromophores

“…Significant interest has been shown in the development of thermochromic polymer blends of a supporting thermoplastic polymer matrix containing small amounts (0.01–3 wt%) of dispersed chromogenic sensor dyes . Kinetically trapped molecular dyes inside the glassy amorphous phase of host polymers can be thermally driven to aggregate, thus returning to the thermodynamically favoured stacked structure above a certain threshold temperature; the consequent emission variation produces the sensing mechanism ( thermochromic effects ).…”

Association phenomena of a chiral perylene derivative in solution and in poly(ethylene) dispersion

“…Interestingly, the equilibrium between the isolated non-interacting form and the aggregated form of perylene chromophores is demonstrated to be easily perturbed by several stimuli, triggered for example by chemical or temperature changes of the environment [17]. In connection with these findings we have recently reported the possibility to transfer the optical responsiveness of perylene derivatives to solid state materials: the aggregation-disaggregation process for dispersed perylene dyes into polymers appeared promising for the preparation of highly efficient optical indicators sensitive to different external stimuli [18][19][20]. A possible fruitful way to engineer even more efficient optical plastic devices is represented by the use of chiral perylene derivatives, whose optical response may result more sensitive to conformational variations induced by the physicochemical solicitations.…”