Nanofiber Web with Controllable Solid Volume Fraction via Calendering
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Solution Overview
Problem
Conventional nanofiber web structures are weak and require support, with the calendering process used to secure them, but this method lacks precise control over the solid volume fraction, a critical performance determinant.
Innovation Solution
The development of novel nanofiber web structures with controllable properties such as fiber diameter, basis weight, and solid volume fraction, achieved by using nanofibers with specific diameters and distributions in contact with supporting structures like meshes, allowing for precise control of the nanofiber web's composition and structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If calendering process is used to secure nanofiber web on fibrous media, then nanofiber web is permanently secured and solid volume fraction increases, but manufacturing precision of solid volume fraction is poor
Solution Approach 1:
The patent applies parameter changes by systematically varying calendering parameters (pressure, temperature, speed, nip width) to achieve precise control over solid volume fraction. The process transforms the uncontrolled compaction into a precisely regulated operation where each parameter can be adjusted independently to target specific solid volume fraction values, thereby resolving the contradiction between securing the web and controlling the fraction precisely.
2Quantity of substance
If nanofiber web is made with low solid volume fraction to maintain porosity, then porosity is preserved, but structural strength decreases
Solution Approach 1:
The patent uses parameter changes to achieve the optimal balance between porosity and strength by controlling solid volume fraction within a specific range (20-80%). This parameter optimization allows the nanofiber web to maintain sufficient porosity for filtration functionality while achieving adequate structural strength through precise control of fiber packing density during the calendering process.
Data Source
AI summary
Disclosed herein are nanofiber structures, and methods of making and using the same. In some embodiments, provided is a porous sheet comprising a plurality of nanofibers in contact with a supporting structure comprising a plurality of supporting elements, wherein: the nanofibers have an average diameter of about 10-900 nm; the supporting elements have an average thickness less than, about equal to, or greater than that of the thickness of the nanofibers; the sheet has an average thickness that is about 75%-150% of an average thickness of the supporting elements; a total volume of the nanofibers is less than about 20% of a total volume of the porous sheet; and/or a total volume of the supporting structure is less than about 50% of the total volume of the porous sheet. In some embodiments, provided is a multilayer structure comprising one or more sections, where each section independently comprises one or more porous sheets as described herein.