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Title: Strong size-dependent stress relaxation in electrospun polymer nanofibers

Abstract

Here, electrospun polymer nanofibers have garnered significant interest due to their strong size-dependent material properties, such as tensile moduli, strength, toughness, and glass transition temperatures. These properties are closely correlated with polymer chain dynamics. In most applications, polymers usually exhibit viscoelastic behaviors such as stress relaxation and creep, which are also determined by the motion of polymer chains. However, the size-dependent viscoelasticity has not been studied previously in polymer nanofibers. Here, we report the first experimental evidence of significant size-dependent stress relaxation in electrospun Nylon-11 nanofibers as well as size-dependent viscosity of the confined amorphous regions. In conjunction with the dramatically increasing stiffness of nano-scaled fibers, this strong relaxation enables size-tunable properties which break the traditional damping-stiffness tradeoff, qualifying electrospun nanofibers as a promising set of size-tunable materials with an unusual and highly desirable combination of simultaneously high stiffness and large mechanical energy dissipation.

Authors:
 [1];  [2];  [1];  [1]
  1. Univ. of California, San Diego, La Jolla, CA (United States)
  2. Argonne National Lab. (ANL), Argonne, IL (United States)
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Science Foundation (NSF)
OSTI Identifier:
1421770
Alternate Identifier(s):
OSTI ID: 1361718
Grant/Contract Number:
AC02-06CH11357
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 121; Journal Issue: 1; Journal ID: ISSN 0021-8979
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING

Citation Formats

Wingert, Matthew C., Jiang, Zhang, Chen, Renkun, and Cai, Shengqiang. Strong size-dependent stress relaxation in electrospun polymer nanofibers. United States: N. p., 2017. Web. doi:10.1063/1.4973486.
Wingert, Matthew C., Jiang, Zhang, Chen, Renkun, & Cai, Shengqiang. Strong size-dependent stress relaxation in electrospun polymer nanofibers. United States. doi:10.1063/1.4973486.
Wingert, Matthew C., Jiang, Zhang, Chen, Renkun, and Cai, Shengqiang. Wed . "Strong size-dependent stress relaxation in electrospun polymer nanofibers". United States. doi:10.1063/1.4973486. https://www.osti.gov/servlets/purl/1421770.
@article{osti_1421770,
title = {Strong size-dependent stress relaxation in electrospun polymer nanofibers},
author = {Wingert, Matthew C. and Jiang, Zhang and Chen, Renkun and Cai, Shengqiang},
abstractNote = {Here, electrospun polymer nanofibers have garnered significant interest due to their strong size-dependent material properties, such as tensile moduli, strength, toughness, and glass transition temperatures. These properties are closely correlated with polymer chain dynamics. In most applications, polymers usually exhibit viscoelastic behaviors such as stress relaxation and creep, which are also determined by the motion of polymer chains. However, the size-dependent viscoelasticity has not been studied previously in polymer nanofibers. Here, we report the first experimental evidence of significant size-dependent stress relaxation in electrospun Nylon-11 nanofibers as well as size-dependent viscosity of the confined amorphous regions. In conjunction with the dramatically increasing stiffness of nano-scaled fibers, this strong relaxation enables size-tunable properties which break the traditional damping-stiffness tradeoff, qualifying electrospun nanofibers as a promising set of size-tunable materials with an unusual and highly desirable combination of simultaneously high stiffness and large mechanical energy dissipation.},
doi = {10.1063/1.4973486},
journal = {Journal of Applied Physics},
number = 1,
volume = 121,
place = {United States},
year = {Wed Jan 04 00:00:00 EST 2017},
month = {Wed Jan 04 00:00:00 EST 2017}
}

Journal Article:
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  • The construction of a trypsin reactor in a chromatography column for rapid and efficient protein digestion in proteomics is described. Electrospun and alcohol-dispersed polymer nanofibers were used for the fabrication of highly stable trypsin coating, which was prepared by a two-step process of covalent attachment and enzyme crosslinking. In a comparative study with the trypsin coatings on asspun and non-dispersed nanofibers, it has been observed that a simple step of alcohol dispersion improved not only the enzyme loading but also the performance of protein digestion. In-column digestion of enolase was successfully performed in less than twenty minutes. By applying themore » alcohol dispersion of polymer nanofibers, the bypass of samples was reduced by filling up the column with well-dispersed nanofibers, and subsequently, interactions between the protein and the enzymes were improved yielding more complete and reproducible digestions. Regardless of alcohol-dispersion or not, trypsin coating showed better digestion performance and improved performance stability under recycled uses than covalently-attached trypsin. The combination of highly stable trypsin coating and alcoholdispersion of polymer nanofibers has opened up a new potential to develop a trypsin column for on-line and automated protein digestion.« less
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  • Uniform nylon-6 nanofibers with diameters around 200 nm were prepared by electrospinning. Polymorphic phase transitions and crystal orientation of nylon-6 in unconfined (i.e., as-electrospun) and a high T{sub g} (340 C) polyimide confined nanofibers were studied. Similar to melt-spun nylon-6 fibers, electrospun nylon-6 nanofibers also exhibited predominant, metastable {gamma}-crystalline form, and the {gamma}-crystal (chain) axes preferentially oriented parallel to the fiber axis. Upon annealing above 150 C, {gamma}-form crystals gradually melted and recrystallized into thermodynamically stable {alpha}-form crystals, which ultimately melted at 220 C. Release of surface tension accompanied this melt-recrystallization process, as revealed by differential scanning calorimetry. For confinedmore » nanofibers, both the melt-recrystallization and surface tension release processes were substantially depressed; {gamma}-form crystals did not melt and recrystallize into {alpha}-form crystals until 210 C, only 10 C below the T{sub m} at 220 C. After complete melting of nanoconfined crystals at 240 C and recrystallization at 100 C, only {alpha}-form crystals oriented perpendicular to the nanofiber axis were obtained. In the polyimide-confined nanofibers, the Brill transition (from the monoclinic {alpha}-form to a high-temperature monoclinic form) was observed at 180-190 C, which was at least 20 C higher than that in unconfined nylon-6 at {approx}160 C. This, again, was attributed to the confinement effect.« less