學術出版;;Publications

Permanent URI for this communityhdl:11536/1

收集所有交通大學研究人員與學生個人或團體所發表之各項學術著作，涵蓋期刊論文、教師專書、學位論文等項。;;Collections of Publications of NCTU Researchers and Students Like Journal Papers and Thesis.

Browse

🏛️國立陽明交通大學機構典藏

Search Results

Now showing 1 - 10 of 10

The Effect of Solvent Vapor Annealing on Drug-Loaded Electrospun Polymer Fibers
(2020-02-01)
Chiu, Yu-Jing
;
Zhang, Ziwei
;
Dziemidowicz, Karolina
;
Nikoletopoulos, Christos-Georgios
;
Angkawinitwong, Ukrit
Electrospinning has emerged as a powerful strategy to develop controlled release drug delivery systems but the effects of post-fabrication solvent vapor annealing on drug-loaded electrospun fibers have not been explored to date. In this work, electrospun poly(epsilon-caprolactone) (PCL) fibers loaded with the hydrophobic small-molecule spironolactone (SPL) were explored. Immediately after fabrication, the fibers are smooth and cylindrical. However, during storage the PCL crystallinity in the fibers is observed to increase, demonstrating a lack of stability. When freshly-prepared fibers are annealed with acetone vapor, the amorphous PCL chains recrystallize, resulting in the fiber surfaces becoming wrinkled and yielding shish-kebab like structures. This effect does not arise after the fibers have been aged. SPL is found to be amorphously dispersed in the PCL matrix both immediately after electrospinning and after annealing. In vitro dissolution studies revealed that while the fresh fibers show a rapid burst of SPL release, after annealing more extended release profiles are observed. Both the rate and extent of release can be varied through changing the annealing time. Further, the annealed formulations are shown to be stable upon storage.
Alignment-Improved and Diameter-Reduced Electrospun Polymer Fibers via the Hot-Stretching Process
(1970-01-01)
Hsu, Hsun-Hao
;
Chiu, Yu-Jing
;
Li, Jia-Wei
;
Tseng, Hsiao-Fan
;
Chang, Kai-Chieh
Electrospinning is one of the most facile and versatile techniques to prepare polymer fibers ranging from micrometers to nanometers. Although several parameters can be tuned to control the sizes and morphologies of electrospun fibers, many obstacles are still encountered as the target sizes of the fibers are getting smaller; for example, the sizes of the fibers can be effectively reduced by lowering the polymer solution concentrations but beaded or beads-on-string structures are usually formed. To overcome such obstacles, here a simple technique to prepare alignment-improved and diameter-reduced fibers without bead formation by hot-stretching electrospun fibers at temperatures higher than the glass transition temperatures of the polymers is developed. Polystyrene and poly(methyl methacrylate) are both used in this work as model materials. The relationship between the draw ratio and diameter of the fibers is quantitatively analyzed, demonstrating the control of the fiber diameters. Moreover, higher degrees of alignment improvement at the middle part of the fibers than those at the end part is observed, which results in lower water contact angles at the middle part of the fibers. This work provides a useful post-treatment technique to control the sizes and orientations of electrospun polymer fibers.
Hierarchical and Spiral Polymer Structures: Direct Electrospinning on Porous Anodic Aluminum Oxide Templates
(2019-08-01)
Liu, Ying-Hsuan
;
Chiu, Yu-Jing
;
Chen, Jiun-Tai
;
交大名義發表
;
應用化學系
Electrospun fibers with hierarchical structures have attracted a great deal of attention because they have distinct properties, such as large specific surface areas and high surface area-to-volume ratios, and can be applied to various fields. Here, a simple and versatile method is demonstrated to prepare electrospun fibers with hierarchical structures by directly electrospinning poly(methyl methacrylate) (PMMA) solutions on porous anodic aluminum oxide (AAO) templates. Hierarchical PMMA structures with micro- and nanometer scales can be generated. The two length scales of the hierarchical structures can be independently controlled; the first length scale is controlled by the electrospinning conditions, and the second length scale is controlled by the pore sizes of the AAO templates. By adding water in the polymer solutions, the evaporation of the solvents and the whipping instability of the solution jets can be manipulated. Consequently, spiral and hierarchical structures can be obtained. This study opens a promising avenue in fabricating electrospun polymer fibers with hierarchical structures, which should have great potential in a variety of applications, such as filtration, diagnosis, and tissue regeneration.
Hierarchical and Spiral Polymer Structures: Direct Electrospinning on Porous Anodic Aluminum Oxide Templates
(1970-01-01)
Liu, Ying-Hsuan
;
Chiu, Yu-Jing
;
Chen, Jiun-Tai
;
交大名義發表
;
應用化學系
Electrospun fibers with hierarchical structures have attracted a great deal of attention because they have distinct properties, such as large specific surface areas and high surface area-to-volume ratios, and can be applied to various fields. Here, a simple and versatile method is demonstrated to prepare electrospun fibers with hierarchical structures by directly electrospinning poly(methyl methacrylate) (PMMA) solutions on porous anodic aluminum oxide (AAO) templates. Hierarchical PMMA structures with micro- and nanometer scales can be generated. The two length scales of the hierarchical structures can be independently controlled; the first length scale is controlled by the electrospinning conditions, and the second length scale is controlled by the pore sizes of the AAO templates. By adding water in the polymer solutions, the evaporation of the solvents and the whipping instability of the solution jets can be manipulated. Consequently, spiral and hierarchical structures can be obtained. This study opens a promising avenue in fabricating electrospun polymer fibers with hierarchical structures, which should have great potential in a variety of applications, such as filtration, diagnosis, and tissue regeneration.
Fabrication and Thermal Insulation Properties of Bamboo-Shaped Polymer Fibers by Selective Solvent Vapor Annealing
(2018-12-01)
Chiu, Yu-Jing
;
Chiu, Han-Lun
;
Tseng, Hsiao-Fan
;
Wu, Bo-Hao
;
Li, Jia-Wei
Fibrillar materials have gained much attention recently because of their unique properties and potential applications. Although many methods have been developed to fabricate materials, it remains challenging to prepare fibrillar materials containing multicomponent materials or even with complex structures. Here, a facile strategy is developed to fabricate bamboo-shaped fibers by treating electrospun polymer core-shell fibers with solvent vapor annealing. Electrospun polystyrene (PS)/poly(methyl methacrylate) (PMMA) core-shell fibers are first prepared by electrospinning PS/PMMA blend solutions via a phase separation process. When the PS/PMMA core-shell fibers are annealed with the vapor of cyclohexane, which swells and delocalizes the PS domains selectively, the fibers transform into bamboo-shaped structures. The bamboo-shaped structures can be further examined by swelling and delocalizing the PMMA domains selectively, revealing the undulated PS structures. The thermal insulation properties of the fibers with bamboo-shaped structures are observed to be enhanced compared with the original polymer core-shell fibers.
Plateau-Rayleigh Instability Morphology Evolution (PRIME): From Electrospun Core-Shell Polymer Fibers to Polymer Microbowls
(2017-03-01)
Chiu, Yu-Jing
;
Tseng, Hsiao-Fan
;
Lo, Yu-Ching
;
Wu, Bo-Hao
;
Chen, Jiun-Tai
Electrospun core-shell fibers have great potentials in many areas, such as tissue engineering, drug delivery, and organic solar cells. Although many core-shell fibers have been prepared and studied, the morphology transformation of core-shell fibers have been rarely studied. In this work, the morphology evolution of electrospun core-shell polymer fibers driven by the Plateau-Rayleigh instability is investigated. Polystyrene/poly(methyl methacrylate) (PS/PMMA) core-shell fibers are first prepared by using blend solutions and a single axial electrospinning setup. After PS/PMMA core-shell fibers are annealed on a PS film, the fibers undulate and sink into the polymer film, forming core-shell hemispheres. The evolution process, which can be observed in situ by optical microscopy, is mainly driven by achieving lower surface and interfacial energies. The morphologies of the transformed structures can be confirmed by a selective removal technique, and polymer microbowls can be obtained.
M Breaking embedded electrospun fibers (BEEF): Fabrication of polymer spheres encapsulated in polymer films
(2016-12)
Chi, Heng-Yu
;
Tsai, Chia-Chan
;
Chiu, Yu-Jing
;
Chen, Jiun-Tai
;
應用化學系
In this work, a novel method to fabricate polymer spheres encapsulated in polymer films by breaking embedded electrospun fibers (BEEF) was developed. Polymer fibers were first prepared by electrospinning and embedded in other polymer films using a three-layer deposition method. After thermal annealing, the electrospun fibers transform into individual spheres with regular spacing and sizes. Poly(methyl methacrylate) (PMMA) and polystyrene (PS) are both used as the fiber or film materials. The transformation process can be observed in-situ by optical microscope (OM) and is similar to the Plateau-Rayleigh instability. The growth rates of the surface undulation of the fibers are calculated, and higher growth rates are observed at higher annealing temperatures. The sizes of the encapsulated polymer spheres agree well with the theoretical predictions. (c) 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016, 54, 2463-2470
Fabrication of Electrospun Polymer Fibers with Nonspherical Cross-Sections Using a Nanopressing Technique
(2016-02)
Chen, Jiun-Tai
;
Kao, Yi-Huei
;
Kuo, Tyng-Yow
;
Liu, Chih-Ting
;
Chiu, Yu-Jing
The fabrication of electrospun polymer fibers is demonstrated with anisotropic cross-sections by applying a simple pressing method. Electrospun polystyrene or poly(methyl methacrylate) fibers are pressed by flat or patterned substrates while the samples are annealed at elevated temperatures. The shapes and morphologies of the pressed polymer fibers are controlled by the experimental conditions such as the pressing force, the pressing temperature, the pressing time, and the surface pattern of the substrate. At the same pressing force, the shape changes of the polymer fibers can be controlled by the pressing time. For shorter pressing times, the deformation process is dominated by the effect of pressing and fibers with barrel-shaped cross-sections can be generated. For longer pressing times, the effect of wetting becomes more important and fibers with dumbbell-shaped cross-sections can be obtained. Hierarchical polymer fibers with nanorods are fabricated by pressing the fibers with porous anodic aluminum oxide templates.
Fabrication, Morphology Control, and Electroless Metal Deposition of Electrospun ABS Fibers
(2016-08)
Chiu, Yu-Jing
;
Chi, Mu-Huan
;
Liu, Ying-Hsuan
;
Chen, Jiun-Tai
;
交大名義發表
Acrylonitrile-butadiene-styrene (ABS) is a polymer composing of acrylonitrile, butadiene, and styrene. It has been widely used in industry because of its good mechanical and physical properties. The fabrication of ABS fibers, however, has been rarely studied. Here the fabrication of ABS fibers has been reported by an electrospinning technique, in which the sizes and morphologies of the fibers can be controlled by adjusting the electrospinning conditions. The morphologies of the ABS fibers can also be transformed by annealing the fibers on poly (methyl methacrylate) (PMMA) films. After annealing, the ABS fibers gradually transform to ABS particles embedded in the PMMA films by a mechanism similar to the Rayleigh-instability-type transformation. To extend the applications of the electrospun ABS fibers, electroless deposition of copper is also conducted, resulting in copper-coated ABS fibers.
Effect of Thermal Annealing on the Surface Properties of Electrospun Polymer Fibers
(2014-02-01)
Chen, Jiun-Tai
;
Chen, Wan-Ling
;
Fan, Ping-Wen
;
Yao, I-Chun
;
應用化學系
Electrospun polymer fibers are gaining importance because of their unique properties and applications in areas such as drug delivery, catalysis, or tissue engineering. Most studies to control the morphology and properties of electrospun polymer fibers focus on changing the electrospinning conditions. The effects of post-treatment processes on the morphology and properties of electrospun polymer fibers, however, are little studied. Here, the effect of thermal annealing on the surface properties of electrospun polymer fibers is investigated. Poly(methyl methacrylate) and polystyrene fibers are fist prepared by electrospinning, followed by thermal annealing processes. Upon thermal annealing, the surface roughness of the electrospun polymer fibers decreases. The driving force of the smoothing process is the minimization of the interfacial energy between polymer fibers and air. The water contact angles of the annealed polymer fibers also decrease with the annealing time.

學術出版;;Publications

Browse

Filters

Settings

Sort By

Results per page

🏛️國立陽明交通大學機構典藏

Search Results