Achieving reversible thermochromism of bisdiynamide polydiacetylene via self-assembling in selected solvents

Chiral Amine-Induced Assembly of Toroidal Structures with a Carboxylic Acid-Functionalized, Polymerizable Macrocyclic Diacetylene

Forming toroidal structures through self-assembly strategies on a small scale poses significant challenges due to the bending energy barriers involved. Herein, we present the chiral amine-induced fabrication of toroidal structures assembled with a carboxylic acid-functionalized macrocyclic diacetylene (MCDA-COOH/PEA). The formation of microtoroids follows an interesting, heat-induced morphological transition pathway, starting from seeds to the sphere and eventually forming stable microtoroids. The structural arrangements of the microtoroids were analyzed through spectroscopic techniques and X-ray diffraction. These microtoroids further undergo topochemical polymerization upon UV light irradiation, resulting in a blue-phase polymeric PDA structure. This study demonstrates the role of chiral control, intermolecular interactions, and molecular rearrangement via energy minimization in a heat-induced morphological transition pathway. This process induces curvature between adjacent building blocks, promoting the formation of stable toroidal structures with minimized free energy. This study presents a promising self-assembly approach to constructing highly organized functional architectures.

Multispectral and Circular Polarization-Sensitive Carbon Dot-Polydiacetylene Capacitive Photodetector

Multispectral photodetectors (MSPs) and circularly polarized light (CPL) sensors are important in opto-electronics, photonics, and imaging. A capacitive photodetector consisting of an interdigitated electrode coated with carbon dot/anthraquinone-polydiacetylene is constructed. Photoexcitation of the carbon dots induces transient electron transfer to the anthraquinone moieties, and concomitant change in the film dielectric constant and recorded capacitance. This unique photodetection mechanism furnishes wavelength selectivity that is solely determined by the absorbance of the carbon dots incorporated in the anthraquinone-polydiacetylene matrix. Accordingly, employing an array of polymerized-anthraquinone photodetector films comprising carbon dots (C-dots) exhibiting different excitation wavelengths yielded optical "capacitive fingerprints" in a broad spectral range (350-650 nm). Furthermore, circular light polarization selectivity is achieved through chiral polymerization of the polydiacetylene framework. The carbon dot/anthraquinone-polydiacetylene capacitive photodetector features rapid photo-response, high fidelity, and recyclability as the redox reactions of anthraquinone are fully reversible. The carbon dot/anthraquinone-polydiacetylene platform is inexpensive, easy to fabricate, and consists of environmentally friendly materials.