24-09-2012, 01:27 PM
Determination of Electrospun Fiber Diameter Distributions Using Image
Analysis Processing
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Abstract:
An image analysis processing method for the measurement of nanofiber diameter was developed. For the
analysis, scanning electron microscopy (SEM) images of electrospun fiber were prepared and applied to the individual
measurement of the fiber diameter by using the developed and the traditional manual methods. Both methods
provided a similar fiber distribution. The fiber average diameters were similar but the variance of the new method
was larger than that of the manual method. The average diameters from the two methods exhibited a linear relationship
with a high coefficient. The developed method can be used as a practical tool to estimate the fiber diameter of
the electrospun web.
Introduction
Electrospinning is one of the most efficient processes for
nanofiber production by charging high voltage to polymer
solutions or melts. It is considered as the most potential
techniques for industrialization due to its simple mechanism
and various applicable polymers.
Previous researches in electrospinining have been focused
on the effects of material properties and processing parameters
on the spinability and the diameters of spun fibers using
various polymers and solvents.1-10 It was found that the fiber
diameter was generally decreased to a certain limit as the
applied voltage and TCD (Tip to Collector Distance) increased.
However the fiber diameter was increased over a certain
TCD level while higher voltage did not show significant effect
on the fiber diameter. The effects can be explained in terms
of the electrical field strength. Also the effects of material
parameters were studied in terms of the concentration, viscosity
and surface tension of polymer solution using various
polymers and solutions. They found that the fiber diameter
of the electrospun web was strongly depending on the polymer
concentration, viscosity and surface tension.
Comparison of Manual Analysis to Image Analysis.
In order to test the reliability of the developed method, the
fiber diameter distributions of several electrospun web images
(Figure 6) determined by manual and the developed methods
were compared.
The averages and variances of fiber diameters for each
image obtained by both methods were summarized in Table II.
The average diameters from both methods gave similar
values for every case. It revealed that the new method can
determine the average fiber diameter in correct. However
they showed small difference in their variance. It can be
explained in terms of sample number used for population
variation estimation. While small number of sample was
used in manual analysis, the developed process used at least
5000 measurements for the variation estimation.
Conclusions
The developed method using image analysis technique
successfully estimate the fiber diameters produced by elec-
trospinning. The developed method and the manual method
did not showed significant difference in the fiber diameter
distributions. Both the methods provide similar fiber average
diameters, while the variances from the image analysis
were 50-200% larger than those from the manual method.
The regression analysis confirms that two methods give the
same values. It reveals that the developed method can be
used as a practical tool to estimate the fiber diameter of
electrospun web.