Hierarchical Omniphobic Surfaces via Thermal Polymer Shrinking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for fabricating hierarchical omniphobic surfaces are not scalable for large-area applications and are not compatible with flexible film substrates, limiting their use in various forms and forms of substrates, especially in medical devices and food packaging where anti-biofouling properties are required.
Innovation Solution
A scalable all-solution-based method using shrinkable polymeric materials with hierarchical structures, incorporating nanoparticle layers and fluorosilane layers, which are activated and heat-shrunk to create microscale and nanoscale features, providing omniphobic properties without the need for lubricants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If photolithography, electrospinning, or reactive ion etching are used to create hierarchical omniphobic surfaces, then high contact angle and low sliding angle are achieved, but the fabrication process becomes difficult to scale up for large area applications
Solution Approach 1:
The patent replaces complex mechanical and chemical fabrication processes (photolithography, electrospinning, reactive ion etching) with a simple thermal shrinking mechanism. The pre-strained polymer substrate, when heated above its glass transition temperature, automatically shrinks to form hierarchical wrinkles, eliminating the need for complex equipment and multiple processing steps while maintaining high omniphobic performance.
Solution Approach 2:
The invention utilizes the glass transition phase change of the polymer substrate. By heating the pre-strained polymer above its glass transition temperature, the material transitions from a rigid strained state to a flexible shrunk state, causing automatic formation of hierarchical wrinkled structures. This phase transition-driven approach enables scalable fabrication without complex processing.
2Productivity
If laser ablation or microfluidic emulsion templating are used to solve scalability challenges, then large area fabrication is enabled, but the physical and chemical processing steps are not compatible with flexible film substrates
Solution Approach 1:
The patent replaces incompatible physical and chemical processing steps (laser ablation, microfluidic emulsion templating) with a purely thermal mechanical shrinking process. This substitution allows the use of flexible, transparent, and biocompatible polymer substrates that can be heat-shrunk without damage, greatly expanding substrate compatibility while maintaining scalability.
Solution Approach 2:
The invention specifically employs flexible polymer substrates (polycarbonate, polyethylene terephthalate, polydimethylsiloxane) that can be heat-shrunk to form the omniphobic surface. These flexible thin films are compatible with a wide range of applications including medical devices and packaging, whereas rigid substrates used in laser ablation cannot be universally applied.
3Manufacturing precision
If sputtering, spin coating, or electrodeposition are used to deposit the stiff layer for wrinkling, then hierarchical structures are formed, but these techniques are not applicable to large area and high volume manufacturing
Solution Approach 1:
The patent replaces vacuum-based sputtering, solvent-based spin coating, and electrochemical electrodeposition with a simple thermal shrinking process. The hierarchical structures form automatically through the mechanical shrinking of pre-strained polymer, eliminating the need for complex deposition equipment and enabling large-area, high-volume manufacturing with improved ease of manufacture.
Solution Approach 2:
The pre-strained polymer substrate serves its own function of creating the stiff layer needed for wrinkling. When heated, the substrate itself shrinks to form the hierarchical wrinkled structure, eliminating the need for separate deposition steps to create the stiff coating. This self-service approach greatly simplifies the manufacturing process.
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 method enables the creation of flexible omniphobic surfaces that effectively repel liquids with various surface tensions, reduce bacterial contamination, and prevent biofilm formation, making them suitable for a wide range of substrates and applications, including medical devices and food packaging.
Implementation Method 1
heated to produce wrinkled microscale features
Implementation Method 2
chemical modification with an omniphobic molecule, such as a fluorosilane, which reduces the surfaces energy
Implementation Method 3
deposited with nanoparticles to provide the nanoscale features
Implementation Method 4
due to the entrapment of air pockets within the structures (Cassie state)
Data Source
AI summary
This application relates to omniphobic materials which are physically and chemically modified at their surface to create hierarchically structured materials with both nanoscale and microscale structures that provide the omniphobic properties. Methods of making such omniphobic surfaces with hierarchical structures and uses thereof, including as flexible films that repel contaminants are also disclosed in the application.