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Simultaneous improvement in dielectric, water resistance and mechanical properties of polyimide (PI) films is critical for their practical use, but difficult to achieve. Herein, a sandwich‐type porous GO/PI film with excellent comprehensive properties was obtained through integrating a GO‐containing complex, fluorine‐containing porous structure and sandwich‐type distribution of porous structure by a simple, low‐cost and green breath figure method. With the addition of only a small amount of GO‐containing complex, a low dielectric constant of 2.21, water absorption of 0.51%, increment in dielectric constant after moisture treatment of 1.60% and high tensile strength of 113.1 MPa, tensile modulus of 1.70 GPa, with 35.39%, 79.42%, 81.81% of reduction and 17.22%, 21.43% of increase compared to PI film were shown, respectively. Moreover, these properties could be adjusted through regulating the component and porous structure by changing the parameters of breath figure method. These outstanding properties make the film a promising candidate for high‐performance low‐dielectric materials. [ABSTRACT FROM AUTHOR]

It is important to reduce dielectric constant while maintaining or improving water resistance and mechanical properties for the practical use of porous low-dielectric materials. Herein, a composite film in which GO and fluorinated PI (FPI) contained porous structure located on the surface of flat PI film was prepared by the simple breath figure method. The incorporation of GO/surfactant can break the design contradiction between low dielectric constant and high mechanical strength for porous structure, thereby realizing the synchronous promotion of dielectric and mechanical properties. Moreover, the water absorption of composite film was decreased significantly due to the synergy of fluorine atoms, porous structure and GO/surfactant, guarantee its high robustness to humid stress. The dielectric, water resistance and mechanical properties of the composite film could be regulated through varying the casting humidity and GO/surfactant content. A low dielectric constant of 2.3, water absorption of 0.6 % and high tensile strength of 122 MPa, with 31.11 % and 75.88 % of decrease and 26.99 % of increase compared to flat PI film was exhibited with the GO/surfactant loading of only 0.5 wt%. The dielectric constant of composite film is still below 2.5 after moisture treatment. These excellent properties facilitate the application of GO/PI composite film in microelectronics. Mutual restraint between low dielectric constant and high mechanical strength was broken via a porous GO/PI composite film, accompanied by excellent water resistance property. [Display omitted] • A porous GO/PI coating for PI film was fabricated using self-assembly method. • Contradiction between low dielectric constant and high mechanical strength was broken. • The composite film exhibited low dielectric constant and water uptake. • The composite film exhibited excellent environmental adaptability in humid environment. • The mechanical properties were improved when other properties were optimized. [ABSTRACT FROM AUTHOR]

[Display omitted] • rGO based ordered porous film was prepared through a simple self-assembly process. • rGO porous film modified electrode was used for electrochemical detection of DA. • High sensitivity and low detection limit of DA detection was obtained. • Good anti-interference, repeatability, reproducibility and stability were shown. • The sensing performance can be optimized through controlling the porous structure. Development of simple, low-cost and facile electrochemical sensor for DA detection is of great significance for the study and treatment of several neurological and psychiatric disorders. Herein, an innovative integration of honeycomb-patterned ordered porous structure with conductive reduced graphene oxide (rGO) was realized through the convenient breath figure method, in which the self-assembly of nontoxic and inexpensive water droplets were involved. Graphene oxide (GO) can be transferred to organic phase by surfactant via a simple self-assembly process to acquire the GO/surfactant complex, which was used as the casting solution in the breath figure method, and thus the skeleton of the porous structure. After electrochemical reduction, honeycomb-patterned porous rGO film was obtained. The prepared rGO-based porous structure modified electrode exhibited a high sensitivity of 1.18 μA/μM and low detection limit of 0.12 μM to DA detection, which are 2.5 and 0.07 folds to corresponding flat films, and are also comparable or even exceeding several functionalized graphene, GO or rGO composites sensor. In addition, excellent anti-interference, reproducibility, repeatability, long-term stability and good accuracy for DA detection in real samples were shown. Importantly, the porous structure can be easily adjusted by changing the preparation conditions, thereby regulating or optimizing the electrochemical sensing performance. [ABSTRACT FROM AUTHOR]