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Highly recyclable multi-core@shell-like HS-PDA@PEI-SA@PEI beads with interior/surface accessible polyethylenimine have been designed for ultrahigh Cr(vi) sorption performance.

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A phosphorescence-based flexible optical temperature-sensing skin was developed for temperature sensing in intelligent bionic robots and automated medical treatment. 4,4-Diamino diphenyl ether and 4,4′-oxydiphthalic anhydride were combined as polyimide for use as the substrate of the flexible sensor. The substrate was doped with 6 μm MFG particles as temperature probes. Ultrasonic dispersion and thermal imidization were used to prepare a 45-μm-thick flexible temperature sensor. Compared with a traditional electronic-based flexible temperature sensor, the flexible temperature sensor has the advantages of noncontact measurement, a wide range of measurement temperature (−150 to 300 °C), high spatial resolution, and accuracy. It can also survive in harsh environments, including extremely low temperatures and high temperatures, and can withstand large deformations and large stresses. Its flexibility, extreme environmental resistance, and excellent mechanical properties show that it has great potential for wireless temperature measurement.

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In this study, a strategy for the fabrication of zirconia-polyimide (ZrO 2 -PI) nanohybrid films with high permittivity (high-k), thermal stability, and excellent mechanical properties has been developed. A colloidal suspension of ZrO 2 nanorods was prepared using the facile microwave-hydrothermal treatment approach. The ZrO 2 -PI nanohybrid film was fabricated by casting an aqueous solution containing water-soluble poly(amic acid) ammonium salt (PAS) and water-dispersible ZrO 2 nanorods followed by thermal imidization. Atomic force microscopy and scanning electron microscopy images indicated that the ZrO 2 nanorods were uniformly dispersed in the PI matrix. Because of the high permittivity of the ZrO 2 nanorods and good compatibility between polyimide and ZrO 2 as well as the nanosize of ZrO 2 , the permittivity increased to 5.1 as the ZrO 2 concentration reached 10% at 10 Hz, while the dielectric loss was as low as 0.05 at 10 Hz. The prepared ZrO 2 -PI nanohybrid films had excellent heat resistance with quite low coefficients of thermal expansion (CTE), as low as 16.3 ppm/K. The ZrO 2 -PI nanohybrid films have excellent thermal stability and good mechanical flexibility. Moreover, no distinct changes were observed for the PAS solution over a storage time of 3 months, after which the nanohybrid film could still be successfully synthesized by thermal imidization. In addition, the water uptake of the ZrO 2 -PI nanohybrid film was approximately 2.5% under 60% relative humidity. The high stability of the PAS precursor, good flexibility, enhanced permittivity, and low CTE behavior of the ZrO 2 -PI nanohybrid films could make this strategy attractive for the ecofriendly design of dielectric polymer nanohybrids as well as for the fabrication of nanohybrid films with potential applications in high charge-storage capacitors and organic field-effect transistors (OFETs) in the flexible electronics industry.

In this study, a novel diamine monomer containing ester and phenyl moieties, 1,2-diphenylethane-1,2-diyl bis(4-aminobenzoate) (1,2-DPEDBA), was synthesized through a three-step reaction. Using this diamine, a novel polyimide (PI) film was prepared with 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6-FDA) as a counter dianhydride through a typical two-step chemical imidization. For comparison, poly(pyromellitic dianhydride-co-4,4′-oxydianiline) (PMDA-ODA PI) was also synthesized via thermal imidization. The resulting 6-FDA-DPEDBA PI film was not only soluble in common polar solvents with high boiling points, such as N,N-dimethylacetamide (DMAc) and N,N-dimethylformamide (DMF), but also soluble in common low-boiling-point polar solvents, such as chloroform (CHCl3) and dichloromethane (CH2Cl2), at room temperature. The resulting novel PI showed a 5% weight loss temperature (T5d) at 360 °C under a nitrogen atmosphere. The resulting PI film was colorless and transparent with a transmittance of 87.1% in the visible light region ranging from 400 to 760 nm. The water absorption of the novel PI film was of 1.78%. The PI film also possessed a good moisture barrier and hydrophobicity. Furthermore, the resulting PI film displayed a low dielectric constant of 2.17 at 106 Hz at room temperature. In conclusion, the novel PI film exhibited much better optical transparency, lower moisture absorption, and a lower dielectric constant as well as better solubility than the PMDA-ODA PI film, which is insoluble in any solvent, although its thermal stability is not better than that of PMDA-ODA PI.