The Role of Electrical Polarity in Electrospinning and on the Mechanical and Structural Properties of As-Spun Fibers

Electric field strength and polarity in electrospinning processes and their effect on process dynamics and the physical properties of as-spun fibers is studied. Using a solution of the neutral polymer such as poly(methyl methacrylate) (PMMA) we explored the electrospun jet motion issued from a Taylor cone. We focused on the straight jet section up to the incipient stage of the bending instability and on the radius of the disk of the fibers deposited on the collecting electrode. A new correlation formula using dimensionless parameters was found, characterizing the effect of the electric field on the length of the straight jet, L˜E~E˜0.55. This correlation was found to be valid when the spinneret was either negatively or positively charged and the electrode grounded. The fiber deposition radius was found to be independent of the electric field strength and polarity. When the spinneret was negatively charged, L˜E was longer, the as-spun fibers were wider. The positively charged setup resulted in fibers with enhanced mechanical properties and higher crystallinity. This work demonstrates that often-overlooked electrical polarity and field strength parameters influence the dynamics of fiber electrospinning, which is crucial for designing polymer fiber properties and optimizing their collection.

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Detailed Process Analysis of Biobased Polybutylene Succinate Microfibers Produced by Laboratory-Scale Melt Electrospinning

Polymers ◽

10.3390/polym13071024 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1024

Author(s):

Maike-Elisa Ostheller ◽

Naveen Kumar Balakrishnan ◽

Robert Groten ◽

Gunnar Seide

Keyword(s):

Field Strength ◽

Electric Field ◽

Electric Field Strength ◽

Biomedical Applications ◽

Process Analysis ◽

Laboratory Scale ◽

Melt Temperature ◽

Melt Electrospinning ◽

Polybutylene Succinate ◽

Fiber Deposition

Melt electrospinning is widely used to manufacture fibers with diameters in the low micrometer range. Such fibers are suitable for many biomedical applications, including sutures, stents and tissue engineering. We investigated the preparation of polybutylene succinate microfibers using a single-nozzle laboratory-scale device, while varying the electric field strength, process throughput, nozzle-to-collector distance and the temperature of the polymer melt. The formation of a Taylor cone followed by continuous fiber deposition was observed for all process parameters, but whipping behavior was enhanced when the electric field strength was increased from 50 to 60 kV. The narrowest fibers (30.05 µm) were produced using the following parameters: electric field strength 60 kV, melt temperature 235 °C, throughput 0.1 mL/min and nozzle-to-collector distance 10 cm. Statistical analysis confirmed that the electric field strength was the most important parameter controlling the average fiber diameter. We therefore report the first production of melt-electrospun polybutylene succinate fibers in the low micrometer range using a laboratory-scale device. This offers an economical and environmentally sustainable alternative to conventional solution electrospinning for the preparation of safe fibers in the micrometer range suitable for biomedical applications.

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Optical Measurement of the Electric Field Strength in a Gel Insulator

IEEJ Transactions on Electronics Information and Systems ◽

10.1541/ieejeiss.136.1420 ◽

2016 ◽

Vol 136 (10) ◽

pp. 1420-1421

Author(s):

Yusuke Tanaka ◽

Yuji Nagaoka ◽

Hyeon-Gu Jeon ◽

Masaharu Fujii ◽

Haruo Ihori

Keyword(s):

Field Strength ◽

Electric Field ◽

Electric Field Strength ◽

Optical Measurement

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Effect of external magnetic field on lane formation in driven pair-ion plasmas

Journal of Plasma Physics ◽

10.1017/s0022377821000027 ◽

2021 ◽

Vol 87 (2) ◽

Author(s):

Swati Baruah ◽

U. Sarma ◽

R. Ganesh

Keyword(s):

Magnetic Field ◽

External Magnetic Field ◽

Field Strength ◽

Electric Field ◽

Electric Field Strength ◽

Coupling Parameter ◽

Critical Parameters ◽

Coulomb Coupling ◽

Lane Formation ◽

Parameter Values

Lane formation dynamics in externally driven pair-ion plasma (PIP) particles is studied in the presence of external magnetic field using Langevin dynamics (LD) simulation. The phase diagram obtained distinguishing the no-lane and lane states is systematically determined from a study of various Coulomb coupling parameter values. A peculiar lane formation-disintegration parameter space is identified; lane formation area extended to a wide range of Coulomb coupling parameter values is observed before disappearing to a mixed phase. The different phases are identified by calculating the order parameter. This and the critical parameters are calculated directly from LD simulation. The critical electric field strength value above which the lanes are formed distinctly is obtained, and it is observed that in the presence of the external magnetic field, the PIP system requires a higher value of the electric field strength to enter into the lane formation state than that in the absence of the magnetic field. We further find out the critical value of electric field frequency beyond which the system exhibits a transition back to the disordered state and this critical frequency is found as an increasing function of the electric field strength in the presence of an external magnetic field. The movement of the lanes is also observed in a direction perpendicular to that of the applied electric and magnetic field directions, which reveals the existence of the electric field drift in the system under study. We also use an oblique force field as the external driving force, both in the presence and absence of the external magnetic field. The application of this oblique force changes the orientation of the lane structures for different applied oblique angle values.

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Overscreening, Co-Ion-Dominated Electroosmosis, and Electric Field Strength Mediated Flow Reversal in Polyelectrolyte Brush Functionalized Nanochannels

ACS Nano ◽

10.1021/acsnano.0c09248 ◽

2021 ◽

Author(s):

Turash Haque Pial ◽

Harnoor Singh Sachar ◽

Parth Rakesh Desai ◽

Siddhartha Das

Keyword(s):

Field Strength ◽

Electric Field ◽

Electric Field Strength ◽

Flow Reversal ◽

Polyelectrolyte Brush

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Sensor of the electric field strength vector components in the form of three mutually perpendicular square

Journal of Physics Conference Series ◽

10.1088/1742-6596/1791/1/012038 ◽

2021 ◽

Vol 1791 (1) ◽

pp. 012038

Author(s):

S V Biryukov ◽

S S Kolmogorova ◽

A S Kolmogorov

Keyword(s):

Field Strength ◽

Electric Field ◽

Electric Field Strength ◽

Strength Vector

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Investigating the feasibility of cerebellar transcranial direct current stimulation to facilitate post-stroke overground gait performance in chronic stroke: a partial least-squares regression approach

Journal of NeuroEngineering and Rehabilitation ◽

10.1186/s12984-021-00817-3 ◽

2021 ◽

Vol 18 (1) ◽

Author(s):

Dhaval Solanki ◽

Zeynab Rezaee ◽

Anirban Dutta ◽

Uttama Lahiri

Keyword(s):

Field Strength ◽

Electric Field ◽

Electric Field Strength ◽

Chronic Stroke ◽

Least Squares Regression ◽

Significance Level ◽

Gait Performance ◽

Wilcoxon Rank Sum Test ◽

Gait Parameters ◽

The Mean

Abstract Background Investigation of lobule-specific electric field effects of cerebellar transcranial direct current stimulation (ctDCS) on overground gait performance has not been performed, so this study aimed to investigate the feasibility of two lobule-specific bilateral ctDCS montages to facilitate overground walking in chronic stroke. Methods Ten chronic post-stroke male subjects participated in this repeated-measure single-blind crossover study, where we evaluated the single-session effects of two bilateral ctDCS montages that applied 2 mA via 3.14 cm2 disc electrodes for 15 min targeting (a) dentate nuclei (also, anterior and posterior lobes), and (b) lower-limb representations (lobules VIIb-IX). A two-sided Wilcoxon rank-sum test was performed at a 5% significance level on the percent normalized change measures in the overground gait performance. Partial least squares regression (PLSR) analysis was performed on the quantitative gait parameters as response variables to the mean lobular electric field strength as the predictors. Clinical assessments were performed with the Ten-Meter walk test (TMWT), Timed Up & Go (TUG), and the Berg Balance Scale based on minimal clinically important differences (MCID). Results The ctDCS montage specific effect was found significant using a two-sided Wilcoxon rank-sum test at a 5% significance level for 'Step Time Affected Leg' (p = 0.0257) and '%Stance Time Unaffected Leg' (p = 0.0376). The changes in the quantitative gait parameters were found to be correlated to the mean electric field strength in the lobules based on PLSR analysis (R2 statistic = 0.6574). Here, the mean electric field strength at the cerebellar lobules, Vermis VIIIb, Ipsi-lesional IX, Vermis IX, Ipsi-lesional X, had the most loading and were positively related to the 'Step Time Affected Leg' and '%Stance Time Unaffected Leg,' and negatively related to the '%Swing Time Unaffected Leg,' '%Single Support Time Affected Leg.' Clinical assessments found similar improvement in the TMWT (MCID: 0.10 m/s), TUG (MCID: 8 s), and BBS score (MCID: 12.5 points) for both the ctDCS montages. Conclusion Our feasibility study found an association between the lobular mean electric field strength and the changes in the quantitative gait parameters following a single ctDCS session in chronic stroke. Both the ctDCS montages improved the clinical outcome measures that should be investigated with a larger sample size for clinical validation. Trial registration: Being retrospectively registered.

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