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Exceptionally thermostable and soluble aromatic polyimides exhibited light color, transparency, fluorescence, intrinsic ultralow-k and electrical bistability properties.

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A flexible and highly fluorescent aromatic polyimide can be obtained by appropriate control of the intra-molecular charge-transfer effects between the diamine and dianhydride moieties.

As eries of rigid nonconjugated polyimide (PI)based thermally activated delayed fluorescence (TADF) polymers were reported for the first time,b ased on a" TADF-Linker-Host" strategy.A mong of which,t he TADF unit contains at ypical TADF luminous core structure,t he "Host" unit exhibits effective conjugation length that endows polyimide with high triplet energy,a nd the "Linker" unit has an aliphatic ring structure to improve solubility and inhibits intramolecular charge transfer effect. All the TADF polymers exhibit high thermal stability (T g > 308.7 8 8C) and refractive index (1.76-1.79). Remarkably,highly-efficient polymer lightemitting diodes (PLEDs) based on the polymers are successfully realized, leading to am aximal external quantum efficiency of 21.0 %a long with lowe fficiency roll-off.S uch outstanding efficiency is amongst the state-of-the-art performance of nonconjugated PLEDs,confirming the effectiveness of structural design strategy,p roviding helpful and valuable guidance on the development of highly-efficient fluorescent polymer materials and PLEDs.

To investigate the relationship between the molecular structure and biological activity of polypyridyl Ru(II) complexes, such as DNA binding, photocleavage ability, and DNA topoisomerase and RNA polymerase inhibition, six new [Ru(bpy)(2)(dppz)](2+) (bpy=2,2'-bipyridine; dppz=dipyrido[3,2-a:2,',3'-c]phenazine) analogs have been synthesized and characterized by means of (1)H-NMR spectroscopy, mass spectrometry, and elemental analysis. Interestingly, the biological properties of these complexes have been identified to be quite different via a series of experimental methods, such as spectral titration, DNA thermal denaturation, viscosity, and gel electrophoresis. To explain the experimental regularity and reveal the underlying mechanism of biological activity, the properties of energy levels and population of frontier molecular orbitals and excited-state transitions of these complexes have been studied by density-functional theory (DFT) and time-depended DFT (TDDFT) calculations. The results suggest that DNA intercalative ligands with better planarity, greater hydrophobicity, and less steric hindrance are beneficial to the DNA intercalation and enzymatic inhibition of their complexes.

Wearable sensing technologies have been developed rapidly in the last decades for physiological and biomechanical signal monitoring. Much attention has been paid to functions of wearable applications, but comfort parameters have been overlooked. This research presents a developed fabric temperature sensor by adopting fiber Bragg grating (FBG) sensors and processing via a textile platform. This FBG-based quasi-distributed sensing system demonstrated a sensitivity of 10.61 ± 0.08 pm/°C with high stability in various temperature environments. No obvious wavelength shift occurred under the curvatures varying from 0 to 50.48 m−1 and in different integration methods with textiles. The temperature distribution monitored by the developed textile sensor in a complex environment with multiple heat sources was deduced using MATLAB to present a real-time dynamic temperature distribution in the wearing environment. This novel fabric temperature sensor shows high sensitivity, stability, and usability with comfort textile properties that are of great potential in wearable applications.

Luminophores usually suffer from luminescent quenching when introduced into a polymer backbone or side chain, which leads to the inefficient luminescence or even no luminescence of the polymer. In this work, alicyclic imide rings were found to be capable of balancing the donor–acceptor properties between the rigid spacer and the aggregation-induced emission-active fluorophore in light-emitting polymers. Along with the nonplanar and rigid emitter, the suppressed intramolecular charge-transfer effect and interchain disturbance can efficiently preserve the luminescence characteristics of the active center, resulting in high solid-state photoluminescence quantum yields of up to 89%. The amorphous polyimides exhibit excellent thermal properties, such as high glass transition temperature (T g) values (398 °C) and high thermal decomposition temperature (T d) values (538 °C). As far as we know, these luminescent polymer materials are of excellent heat resistance with the highest luminescence efficiency reported. The results have significant impact for the precise prediction of the optical properties of light-emitting polymers by appropriate monomer design, providing controllable ways for synthesizing high thermal stability polymeric materials with efficient fluorescence properties.