Alternating Field Electrode System for AC-Electrospinning
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Solution Overview
Problem
AC-electrospinning processes face limitations due to poor spinnability of many precursors and material accumulation at the electrode's outer edge, leading to reduced fiber production and termination of the process.
Innovation Solution
An electrode system comprising an electrical charging component electrode and at least one of an AC field attenuating component and a precursor liquid attenuating component, which includes a doughnut-shaped or disk-shaped electrical charging component electrode with a reservoir for precursor liquid, and an adjustable AC field or precursor liquid attenuating component made of non-conductive material, to control and enhance fiber generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If AC-electrospinning is used to improve fiber generation rate and productivity, then fiber generation rate increases, but many precursors become poorly spinnable due to stronger field confinement
Solution Approach 1:
A dielectric barrier layer is introduced between the electrode and the precursor solution. This intermediary layer modifies the electric field distribution, reducing field confinement at the electrode surface and enabling better spinnability for previously problematic precursors while maintaining high fiber generation rates
Solution Approach 2:
The patent changes the electrical parameters by using AC voltage instead of DC voltage, and introduces a dielectric barrier that modifies the field strength distribution. This parameter change allows the system to achieve both high productivity and improved precursor spinnability by optimizing the electric field characteristics
2Productivity
If high voltage is applied to non-capillary electrodes to increase productivity, then multiple jets are generated simultaneously, but voltage requirements increase
Solution Approach 1:
The dielectric barrier acts as an intermediary that modifies the electric field distribution, allowing for more efficient voltage utilization. This enables the generation of multiple jets with optimized voltage requirements by improving field confinement control
Solution Approach 2:
The patent employs periodic AC voltage application instead of continuous DC voltage. This periodic action allows for more efficient energy utilization and reduced voltage requirements while maintaining high productivity through the alternating field effect that enhances jet formation
3Productivity
If AC field is applied to enhance corona and ionic wind effects for fiber carry-away, then fiber generation rate increases, but field confinement to electrode increases
Solution Approach 1:
The dielectric barrier serves as a mediator that modifies the electric field distribution pattern. It reduces excessive field confinement to the electrode surface while maintaining the corona and ionic wind effects necessary for high fiber generation rates, thereby balancing field concentration with fiber carry-away efficiency
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The electrode system improves AC-electrospinning productivity, allows generation of previously poorly-spinnable precursors, and reduces material accumulation, achieving better control over fiber generation and propagation.
Implementation Method 1
The electrical charging component electrode is electrically coupled to an AC source that delivers an AC signal to the electrical charging component electrode to place a predetermined AC voltage on the electrical charging component electrode
Implementation Method 2
The AC field attenuating component attenuates an AC field created by the placement of the predetermined AC voltage on the electrical charging component electrode
Implementation Method 3
In electrospinning, fibers are usually made by forcing a polymer-based melt or solution through a capillary needle or from the surface of a layer of liquid precursor on an electrode surface while applying an electric field (DC or AC) to form a propagating polymer jet
Implementation Method 4
AC-electrospinning exhibits a high fiber generation rate per electrode area, high process productivity, and easier handling of fibers in comparison to DC-electrospinning due to the increased effect of the corona or ionic wind phenomenon that efficiently carries away the produced fibers
Data Source
AI summary
An electrode system for use in an AC-electrospinning process comprises an electrical charging component electrode and at least one of an AC field attenuating component and a precursor liquid attenuating component. The electrical charging component electrode is electrically coupled to an AC source that places a predetermined AC voltage on the electrical charging component electrode. In cases in which the electrode system includes the AC field attenuating component, it attenuates the AC field generated by the electrical charging component electrode to better shape and control the direction of the fibrous flow. In cases in which the electrode system includes the precursor liquid attenuating component, it serves to increase fiber generation, even if the top surface of the liquid precursor is not ideally shaped or is below a rim or lip of the reservoir that contains the liquid on the electrical charging component electrode.