Needleless Electrospinning Core-Sheath Fiber Production
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Solution Overview
Problem
Current methods for producing core-sheath fibers, such as extrusion and melt blowing, are not suitable for thermally labile materials like drugs or polypeptides, and conventional electrospinning techniques have limitations in throughput and consistency for producing fibers with diameters less than 20 microns.
Innovation Solution
The method involves optimizing shear stresses at the fluid interface between core and sheath polymers in Taylor cones by controlling aperture geometry, flow rates, and viscosities to achieve a desired polymer ratio in electrospinning jets, using a needleless electrospinning apparatus with elongate vessels and aligned apertures to facilitate high-throughput production of core-sheath fibers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional electrospinning methods are used, then fiber formation is achieved, but throughput is limited and consistency is poor
Solution Approach 1:
The invention divides the single Taylor cone formation process into multiple concurrent Taylor cone formations by using an array of capillary tubes instead of a single needle. This segmentation allows simultaneous production of multiple fibers, dramatically increasing throughput while maintaining consistency through standardized capillary geometries that produce uniform flow and electrospinning conditions for each fiber.
Solution Approach 2:
The invention changes critical parameters including replacing the single-needle configuration with multi-capillary arrays, optimizing voltage distributions across multiple sites, and adjusting flow rates through controlled capillary geometries. These parameter changes enable concurrent multi-fiber production while maintaining uniform fiber properties through standardized manufacturing conditions.
2Productivity
If high volumetric flow rates are used, then production efficiency increases, but fiber diameter control becomes difficult
Solution Approach 1:
By segmenting the total flow into multiple parallel capillary tubes, the system can operate at high total volumetric flow rates while maintaining manageable flow rates per capillary. This segmentation allows high overall productivity without compromising fiber diameter control, as each individual capillary maintains stable, controlled flow conditions suitable for precise diameter control.
Solution Approach 2:
The invention replaces mechanical flow control mechanisms with electrostatic field-based control. By applying optimized voltage distributions across the capillary array, the system controls fiber formation through electrostatic forces rather than mechanical means, enabling high flow rates while maintaining precise fiber diameter control through electrical parameter adjustment.
3Adaptability or versatility
If thermally labile materials are processed, then material compatibility is improved, but process stability becomes more difficult to maintain
Solution Approach 1:
The invention replaces thermal processing mechanisms with electrostatic field-based processing. By using controlled voltage applications to generate Taylor cones and electrospinning jets, the system can process thermally labile materials without subjecting them to high temperatures, thereby maintaining both material compatibility and process stability through non-thermal means.
Solution Approach 2:
The invention changes the fundamental processing parameters from thermal to electrostatic control. By optimizing voltage distributions and flow rates rather than relying on temperature control, the system achieves stable processing of thermally sensitive materials. This parameter change allows the use of low-temperature, electrostatically-driven Taylor cone formation that maintains process stability while accommodating materials with low thermal tolerance.
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
This approach enhances the consistency and efficiency of core-sheath fiber production, allowing for higher volumetric flow rates and improved control over fiber properties, enabling the use of thermally labile materials and reducing production costs.
Implementation Method 1
an electrostatic force is applied to a polymer solution to induce the formation of electrospinning jets which harden to form very fine fibers
Implementation Method 2
optimizing shear stresses at the fluid interface between core and sheath polymers in Taylor cones
Implementation Method 3
optimizing shear stresses at the fluid interface between core and sheath polymers in Taylor cones to achieve a desired polymer ratio
Data Source
AI summary
Systems and methods for electrospinning of core-sheath fibers are provided. The systems and methods achieve optimization of a shear stress that exists at a fluid boundary between core and sheath polymer solutions, by varying certain parameters of an electrospinning apparatus and/or the solutions used therewith.