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Four novel mesogenic dyads consisting of a hexa(alkoxy)triphenylene donor that was linked to a perylene tetracarboxylic esters acceptor by the bridges (O–(CH2)2–O), (O–(CH2)6–O), (O–(CH2)10–O) and (O–(CH2)12–O), had been synthesized. Their structures were characterized by 13C and 1H nuclear magnetic resonance (NMR), infrared spectroscopy (IR) and elemental analysis (EA). The experimental results of cyclic voltammetry and UV/Vis showed the aliphatic linkage of the donor–acceptor dyads preserved the genuine electrochemical behaviors and light absorption properties of the donor and acceptor units, and the energy level difference between the HOMO of the donor and the LUMO of the acceptor is about 1.94 eV. The differential scanning calorimetry (DSC) traces and polarizing optical microscopy (POM) textures confirmed that all dyads had mesophase. When excited at 443 nm, fluorescence quenching process of the acceptor unit was ascribed to a intramolecular ground-state charge transfer from the donor to it. And the fluorescence quenching varying with the bridge lengths were understood by Dexter-type energy transfer theory. These behaviors of photoinduced intramolecular charge transfer and forming columnar liquid crystal phase made these dyads candidates of new active materials in organic solar cells.

Conductive self-healing hydrogels are a new type of functional material that combine self-healing with conductive properties. They are widely used in flexible and stretchable devices, which require not only self-healing properties and electrical conductivity but also good stretchability. In this study, we used a one-pot process to crosslink and polymerize trivalent iron (Fe3+) with acrylic acid (AA) and acrylamide (AM) into a dual network hydrogel P(AA-co-AM)/Fe3+, with both chemically and physically crosslinked networks. The obtained hydrogels exhibited excellent tensile properties (~2000% stretchability) and rapid self-healing ability (complete healing at room temperature within 8 h). Furthermore, the Fe3+ gives the hydrogel good electrical conductivity. In addition, a capacitive pressure sensor using the hydrogel as a conductive active layer was fabricated, which proved its application in the field of wearable devices.

Developing stretchable and self-healable skin-like materials have received increasing research for their broad application in wearable sensors, artificial intelligence, and soft robotics. However, development of skin-like sensor that can combine superior stretchable and self-healing ability is still a challenge. In this work, we designed a tough and self-healing hydrogel by formation of the hydrogen bonds and dual metal-carboxylate coordination bonds among pectin, poly(acrylic acid) and metal ions. The reversible nature of dynamic coordination interactions endowing the hydrogel high stretchability (1214%), excellent recovery property as well as superior self-healing ability (94% healing efficiency in 2 h) without any assistance of external stimuli. The stretchable and self-healable capacitance sensors are based on the hydrogel can detect a large scale of pressures, monitor the multifarious human motions, mimic the function of self-healing and sensation properties of natural skins. This work provides excellent performance of pressure and strain sensors based on the stretchable and self-healable hydrogel, it shows great potential in the field of electronic skin systems.