Spinneret Protrusions Stabilize Electrostatic Nanofiber Spinning
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Solution Overview
Problem
The existing electrostatic spinning methods face challenges in producing uniform nanofibers with low ununiformity in fiber diameter, especially when dealing with starting material fluids of low viscosity, as they tend to result in unstable continuous spinning and uneven fiber production due to interference between Taylor cones and electrical field disruptions.
Innovation Solution
A spinneret with protrusions and flow passages is designed to distribute starting material fluid uniformly across discharge holes, preventing Taylor cone contact and stabilizing the spinning process by generating powerful electrical fields and maintaining equal distances between discharge holes, allowing for the use of a wide viscosity range of starting materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the viscosity of starting material fluid is decreased to produce smaller fiber diameter nanofibers, then the fiber diameter is reduced, but the continuous spinning stability deteriorates and fiber diameter uniformity decreases
Solution Approach 1:
The spinneret is divided into multiple protrusions (at least three) arranged in an array, with each protrusion having a discharge hole at its apex. This segmentation allows the fluid to be distributed across multiple independent discharge points, preventing the interference and contact between Taylor cones that occurs with single or few discharge holes, thereby maintaining spinning stability even with low-viscosity fluids
Solution Approach 2:
Each protrusion is designed with specific local characteristics: a rounded apex with a discharge hole positioned at the tip, and a height of 0.1 mm or more. This local quality optimization ensures that each discharge point generates a stable Taylor cone structure, improving overall fiber diameter uniformity while maintaining continuous spinning stability
2Productivity
If a plurality of fluid separation parts are formed with small intervals to improve nanofiber production, then productivity is increased, but electrical field interference between adjacent injection needles occurs
Solution Approach 1:
The discharge holes are positioned at the apexes of protrusions that extend in the thickness direction of the spinneret. This dimensional arrangement ensures that the pitch between discharge holes exceeds 1 mm, maintaining sufficient electrical field separation while still achieving high productivity through multiple discharge points
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 design enables the productive production of homogeneous and uniform nanofibers with low ununiformity in fiber diameter, even with low-viscosity starting materials, by preventing Taylor cone contact and ensuring stable fluid distribution, thus enhancing spinning stability and quality.
Implementation Method 1
By a powerful electrical field generated by the electrical field concentration effect of the front end of the injection needle, the starting material fluid is attracted in a direction toward the surface of the collecting electrode
Implementation Method 2
when the force which is attracted to the surface of the collecting electrode due to the electrical field exceeds the surface tension of the starting material fluid, the starting material fluid flies out in the form of jet from the front end of the Taylor cone
Data Source
AI summary
A spinneret (1) for electrostatic spinning is configured from a structure of an electrically conductive metal material. The structure is provided with a long-axis direction (X), a short-axis direction (Z), and a thickness direction (Y). An inflow port (10) for a spinning starting material fluid is provided to one surface of the structure. A plurality of protrusions (5) are formed on another surface of the structure so as to be aligned along the long-axis direction (X). Each of the plurality of protrusion (5) extends so as to protrude from the structure. The protrusions (5) have, provided to apexes (2) thereof, discharge holes (4) for discharging the starting material fluid. The pitch of the discharge holes (4) exceeds 1 mm.