4D printing is proposed based on the additive manufacturing of stimuli-responsive materials and structures,which can realize shape changing upon external stimuli.This article reviews the 4D printing methods and actuat...4D printing is proposed based on the additive manufacturing of stimuli-responsive materials and structures,which can realize shape changing upon external stimuli.This article reviews the 4D printing methods and actuating performances of 4D printing structures based on shape memory polymers,hydrogels,liquid crystal elastomers,and electroactive polymers.This article shows that the shape morphing properties of single materials are limited,while 4D printing of composites can integrate the various driving modes of different smart materials.In the end,challenges facing 4D printing such as broadening the scope of smart materials,improving printing processes,the compatibility of printing different materials have been discussed.展开更多
Two 9,10-distyrylanthracene (DSA) derivatives CNDSA and t-BUDSA were designed and synthesized, and their photophysical properties and crystal structures were investigated. Compared to DSA, the maximum emission peaks o...Two 9,10-distyrylanthracene (DSA) derivatives CNDSA and t-BUDSA were designed and synthesized, and their photophysical properties and crystal structures were investigated. Compared to DSA, the maximum emission peaks of the two compounds showed red-shift not only in THF solution, but also in crystals, because the introduction of electron-withdrawing substituents to DSA leads to more dispersion of the electrons in the molecules. The two crystals of CNDSA and t-BUDSA show strong fluores- cence with the efficiency F of 45% and 33%, respectively, which may be resulted from no obvious-interactions between molecules inside the crystal due to the large distance between the two adjacent molecules and nearly no overlap between the central anthracene planes. The analysis of crystal structures of the two compounds indicated that the molecules are arranged in the same conformation and orientation in their crystals, i.e. uniaxially oriented packing crystal, because of the supramolecular interac- tion of CH/ in the two crystals and additional C-H···N interactions in CNDSA.展开更多
基金supported by the National Key Research and Development Program of China(Grant Nos.2018YFB1105100,2018YFC2001300)the National Natural Science Foundation of China(Grant Nos.5167050531,51822504,91848204)+4 种基金the Joint Foundation for Equipment Pre-research of Ministry of Education(Grant No.2018G944J00084)Key Scientific and Technological Project of Jilin Province(Grant No.20180201051GX)the Program for JLU Science and Technology Innovative Research Team(Grant No.2017TD-04)the National Postdoctoral Program for Innovative Talents(Grant No.BX20180126)the China Postdoctoral Science Foundation(Grant No.2018M641769)。
文摘4D printing is proposed based on the additive manufacturing of stimuli-responsive materials and structures,which can realize shape changing upon external stimuli.This article reviews the 4D printing methods and actuating performances of 4D printing structures based on shape memory polymers,hydrogels,liquid crystal elastomers,and electroactive polymers.This article shows that the shape morphing properties of single materials are limited,while 4D printing of composites can integrate the various driving modes of different smart materials.In the end,challenges facing 4D printing such as broadening the scope of smart materials,improving printing processes,the compatibility of printing different materials have been discussed.
基金supported by the National Basic Research Program of China(2013CB834702)the National Natural Science Foundation of China(21074045,21204027,21221063)+1 种基金the Research Fund for the Doctoral Program of Higher Education of Chinathe Project of Jilin Province(20100704)
文摘Two 9,10-distyrylanthracene (DSA) derivatives CNDSA and t-BUDSA were designed and synthesized, and their photophysical properties and crystal structures were investigated. Compared to DSA, the maximum emission peaks of the two compounds showed red-shift not only in THF solution, but also in crystals, because the introduction of electron-withdrawing substituents to DSA leads to more dispersion of the electrons in the molecules. The two crystals of CNDSA and t-BUDSA show strong fluores- cence with the efficiency F of 45% and 33%, respectively, which may be resulted from no obvious-interactions between molecules inside the crystal due to the large distance between the two adjacent molecules and nearly no overlap between the central anthracene planes. The analysis of crystal structures of the two compounds indicated that the molecules are arranged in the same conformation and orientation in their crystals, i.e. uniaxially oriented packing crystal, because of the supramolecular interac- tion of CH/ in the two crystals and additional C-H···N interactions in CNDSA.
