Shape-memory polymers (SMPs) are synthesized with adjustable glass transition temperature (T g ) ranging from 299 to 322 °C, higher than those reported previously. The polyimide containing thermal stable but flexible linkages within the backbone act as reversible phase, and high molecular weight (M n ) is necessary to form physical cross-links as fixed phase of thermoplastic shape-memory polyimide. The critical M n is 21.3 kg/mol, and the relationship between M n and T g is explored. Thermoset polyimides show higher storage modulus and better shape-memory effects than thermoplastic counterparts due to covalent cross-linking, and the effective cross-link density with the influence on their physical properties is studied. The mechanism of high-temperature shape-memory effect of polyimide on the basis of chain flexibility, molecular weight, and cross-link density is proposed, which will benefit further research on high-temperature SMPs.

Y2O3 :  Eu3+ microspheres, with an average diameter of 3 μm, were successfully prepared through a large-scale and facile solvothermal method followed by a subsequent heat treatment. X-ray diffraction, Fourier transform infrared spectroscopy, energy-dispersive X-ray spectra, thermogravimetric and differential thermal analysis, inductive coupled plasma atomic absorption spectrometric analysis, scanning electron microscopy, transmission electron microscopy, photoluminescence spectra, as well kinetic decays, and cathodoluminescence spectra were used to characterize the samples. These microspheres were actually composed of randomly aggregated nanoparticles. The formation mechanisms for the Y2O3 :  Eu3+ microspheres have been proposed on an isotropic growth mechanism. The Y2O3 :  Eu3+ microspheres show a strong red emission corresponding to 5 D 0 → 7 F 2 transition (610 nm) of Eu3+ under ultraviolet excitation (259 nm) and low-voltage electron beams excitation (1−5 kV), which have potential applications in fluorescent lamps and field emission displays.

Luminescence functionalization of the ordered mesoporous SBA-15 silica was realized by depositing a YVO4:Eu3+ phosphor layer on its surface via the Pechini sol-gel process, resulting in the formation of the YVO4:Eu3+@SBA-15 composite material. This material, which combines the mesoporous structure of SBA-15 and the strong red luminescence property of YVO4:Eu3+, can be used as a novel functional drug delivery system. The structure, morphology, porosity, and optical properties of the materials were well characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, N2 adsorption, and photoluminescence spectra. As expected, the pore volume, surface area, and pore size of SBA-15 decrease in sequence after deposition of the YVO4:Eu3+ layer and the adsorption of ibuprofen (IBU, drug). The IBU-loaded YVO4:Eu3+@SBA-15 system still shows the red emission of Eu3+ (617 nm, 5D0-7F2) under UV irradiation and the controlled drug release property. Additionally, the emission intensity of Eu3+ increases with an increase in the cumulative released amount of IBU in the system, making the extent of drug release easily identifiable, trackable, and monitorable by the change of luminescence. The system has great potential in the drug delivery and disease therapy fields.