title: From Nanofibrous Hollow Microspheres to Nanofibrous Hollow Discs and Nanofibrous Shells.
abstract: Nano- and microsized structures are of central importance to advanced materials and nanotechnologies, which have tremendously impacted both biomedical and physical sciences. Herein, novel emulsification and thermally induced phase separation (TIPS) techniques to fabricate linear polymers into nanofibrous hollow objects are reported for the first time. Through manipulating the emulsification conditions, the evolution of the emulsion structure can be controlled and nanofibrous hollow microspheres with a controllable opening size and nano-fibrous shells can be fabricated. Through adjusting the rheological properties of the emulsions, nanofibrous hollow discs are also created. A new mechanistic hypotheses of the nanofibrous hollow object formation is proposed: the nano- and microscaled structures are independently determined by TIPS and the emulsification process, respectively. Guided by this theory, the nanofiber formation conditions for two further additional polymers (polyacrylonitrile and Nylon) under TIPS are identified, and solid/nanofibrous non-hollow/hollow microspheres are created from these two additional polymers under TIPS and emulsification for the first time. Therefore, the developed strategy is applicable to various polymer systems, and can broadly impact nano- and microfabrication technologies.
authors.affiliation: Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109-1078, USA.
authors.forename: Zhanpeng
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109-1078, USA.|Department of Biologic and Materials Sciences, University of Michigan, Ann Arbor, MI, 48109-1078, USA.|Macromolecular Science and Engineering Center, University of Michigan, Ann Arbor, MI, 48109-1078, USA.|Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI, 48109-1078, USA.
authors.forename: Peter X
authors.initials: PX
authors.lastname: Ma
mesh_terms: D004655:Emulsions / Q000737:chemistry; D008863:Microspheres; D057139:Nanofibers / Q000737:chemistry* / Q000648:ultrastructure; D011108:Polymers / Q000737:chemistry; D013501:Surface-Active Agents / Q000737:chemistry; D013696:Temperature
chemical_list: D004655:Emulsions; D011108:Polymers; D013501:Surface-Active Agents
keywords: microstructures; nanofibers; phase separation; polymers; self-assembly