It is shown that due to the inherent irreversible non‐fluorescence to fluorescence transition feature of polydiacetylene (PDA) supramolecules that occurs in response to thermal perturbations, PDA vesicles embedded in a host polymer matrix function as nano/microscale temperature indicators. As a result, they are used to monitor temperature gradients on an integrated circuit chip and to uncover submicrometer size filamentary defects in a resistance random access memory (RRAM) device structure. This new methodology should find a wide applicability in carrying out temperature distribution analysis on semiconductor and micro‐electromechanical system (MEMS) devices where the detection of local heat deviations of small‐scale components is critical. magnified image

advantages. [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] First, chemical initiators or catalysts are not employed for the synthesis of PDA, as they are most often generated by UV or gamma irradiation of self-assembled diacetylene monomers. Therefore, the resulting polymers are not contaminated with undesired by-products. Second, from a materials science perspective, it is fortuitous that molecular engineering of the long alkyl chains and the functional headgroups of PDA results in the formation of a variety of nanostructures including liposomes, fi lms, wires, tubes, plates, and helicies. [ 27 , 28 ] Finally, and most importantly, the PDA aggregates undergo rapid color (blue-to-red) and fl uorescence changes (none-to-red) under the infl uence of environmental stimuli. [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44] Consequently, this smart material in its various nanomanifestations has been extensively used in the detection of various analytes, including biomolecules (virus, DNAs, antibodies, enzymes, ions, etc.) and volatile organic solvents (VOCs), as well as temperature monitoring. During our recent studies aimed at the development of PDA-based smart materials, [ 12 , 42-46 ] we have explored an intriguing idea for the design of magnetically responsive conjugated polymer supramolecules. It is well known that fatty acid containing diacetylenes form nanoaggregates in aqueous environments and that 254 nm UV irradiation of these aqueous diacetylene suspensions results in the formation of PDA supramolecules. [ 50 ] We hypothesized A direct method for the generation of magnetically responsive conjugated polymer supramolecules is described. By immobilizing magnetite nanoparticles (MNP) on the surface of polydiacetylene (PDA) supramolecules, an inorganic/conjugated polymer hybrid system results that enables the incorporation of an important property (magnetism) to an attractive class of colorimetric PDA sensors. Benefi ts of this new system include:(1) ease of preparation, (2) variability in diacetylene labeling of MNPs, (3) diversity in conjugated PDA morphologies, (4) facile isolation process, and (5) immobilization of the PDA without altering the colorimetric (sensory) properties. It is demonstrated that PDA/MNP systems offer advantages in applications including fi lm formation, separation, and sensing.