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Solid-state molecular rotor-type materials such as host-guest inclusion compounds are very desirable for the construction of molecular ferroelectrics. However, they usually have a low Curie temperature (Tc) and uniaxial nature, severely hindering their practical applications. Herein, by regulating the anion to control "momentum matching" in the crystal structure, we successfully designed a high-temperature multiaxial host-guest inclusion ferroelectric [(MeO-C6H4-NH3)(18-crown-6)][TFSA] (MeO-C6H4-NH3 = 4-methoxyanilinium, TFSA = bis(trifluoromethanesulfonyl)ammonium) with the Aizu notation of mmmFm. Compared to the parent uniaxial ferroelectric [(MeO-C6H4-NH3)(18-crown-6)][BF4] with a Tc of 127 K, the introduction of larger TFSA anions brings a lower crystal symmetry at room temperature and a higher energy barrier of molecular motions in phase transition, giving [(MeO-C6H4-NH3)(18-crown-6)][TFSA] multiaxial ferroelectricity and a high Tc up to 415 K (above that of BaTiO3). To our knowledge, such a record temperature enhancement of 288 K makes its Tc the highest among the reported crown-ether-based ferroelectrics, giving a wide working temperature range for applications in data storage, temperature sensing, actuation, and so on. This work will provide guidance and inspiration for designing high-Tc host-guest inclusion ferroelectrics.

A novel flexible Microelectromechanical System(MEMS) anti-drag skin was proposed based on the drag reduction with lingering-micro-bubble generated by electrolysis,and the fabrication of flexible MEMS anti-drag skin was designed.The MEMS skin composed of a flexible substrate layer,a metal electrode layer and a micro-well-array layer was designed,and two process routes based on MEMS were developed for the skin fabrication.Then,the polydimethylsiloxane(PDMS) and SU-8 were used to fabricate the micro-well-array layer,respectively.Several key steps in these processes were studied and a specimen was fabricated using SU-8.The specimen has a thickness of 90 μm and contains 6.25×104 cylindrical wells with a depth of 50 μm and a diameter of 40 μm per square centimeter.It can be bent and attached on a Φ28 mm cylinder without damage.Results demonstrate that the MEMS is feasible to realize the anti-drag skin and the flexible MEMS anti-drag skin offers a novel way to reduce the skin friction of vehicles in water.