From Electrospun Polymer Core–Shell Fibers to Polymer Hemispheres and Spheres: Two Types of Transformation Processes and Tearing Films with Linearly Arranged Cavities

Abstract

Electrospun polymer core−shell fibers have gained much attention because of their promising applications in areas such as electronic devices, drug delivery, and tissue engineering. The morphology transformation of polymer core− shell fibers, however, has been rarely investigated. Here, we study the effect of thermal annealing on the morphology transformation of electrospun polystyrene (PS)/poly(methyl methacrylate) (PMMA) core−shell fibers on PMMA films. Two types of transformation processes are discovered. In the first type of the transformation process (type I), the PS cores transform to hemispherical particles after the annealing process; in the second type of the transformation process (type II), the PS cores transform to spherical particles after the annealing process. The measured sizes of the hemispherical and spherical PS domains fall into two classified regions, as predicted for the two different types of transformation processes. It is also observed that the growth rates of the undulated amplitude are similar for the two different types of transformation processes, but the type I fibers start to undulate at later annealing times than the type II fibers do. When the PS particles are selectively removed, the PMMA films with linearly arranged cavities are used for the tearing experiments, demonstrating a proof of concept on the potentials in studying the mechanical properties of cavity-containing films.

The Effect of Solvent Vapor Annealing on Drug-Loaded Electrospun Polymer Fibers

“…For instance, in previous work electrospun polystyrene (PS)/poly(methyl methacrylate) (PMMA) core-shell fibers were thermally annealed on PMMA films. The PS cores of the fibers were found to break into a serious of spherical particles with distinct spacings to reduce the surface and interfacial energies [18]. Alternatively, solvent vapor annealing can be applied.…”

Fabrication of Electrospun Polymer Nanofibers with Diverse Morphologies

“…Multicomponent fibers are important for applications in the areas of nanosprings [ 112 ], super-hydrophobic surfaces [ 113 , 114 ], sensors [ 115 , 116 ], and drug delivery [ 117 , 118 ]. The core–shell structures, which include a core and any number of shells, are the most prominent multicomponent fibers [ 13 , 119 ]. Accordingly, a modified spinneret with coaxial capillaries has been developed for building these materials [ 120 , 121 ].…”

Sunny-Side-Up Egg-Shaped Structures: Surface Modification To Form Anisotropic Polymer Particles Driven by the Plateau–Rayleigh Instability as Fluorescence Manipulation Platforms

“…Here, we study the Plateau–Rayleigh instability of electrospun polymer core–shell fibers on modified glass substrates. The electrospinning technique is a widely used method that can produce polymer fibers with diameters ranging from micrometers to nanometers; − polymer fibers with multicomponents can also be generated. − In this work, the typical electrospinning technique with polystyrene (PS)/poly­(methyl methacrylate) (PMMA) blend solutions is used to produce electrospun PS/PMMA core–shell fibers. , The PS/PMMA core–shell fibers are then deposited on glass substrates, modified with n -octadecyl­trichlorosilane (ODTS) solutions, for annealing experiments. ODTS is a long-chain alkyl group and has been widely used for the modification of the glass substrates .…”

“…11−14 In this work, the typical electrospinning technique with polystyrene (PS)/ poly(methyl methacrylate) (PMMA) blend solutions is used to produce electrospun PS/PMMA core−shell fibers. 15,16 The PS/PMMA core−shell fibers are then deposited on glass substrates, modified with n-octadecyltrichlorosilane (ODTS) solutions, for annealing experiments. ODTS is a long-chain alkyl group and has been widely used for the modification of the glass substrates.…”