Fluorinated Elastomer Molds for Isolated Nanostructures
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Solution Overview
Problem
Current imprint lithographic techniques face limitations due to the use of materials like PDMS, which swell with organic solvents, react with acidic or basic solutions, and have high surface energy, leading to fidelity issues and scum layer formation, making it difficult to fabricate isolated micro- and nanoscale structures and deliver therapeutic agents effectively.
Innovation Solution
The development of solvent-resistant, low surface energy polymeric materials derived from casting low viscosity liquid materials onto a master template, which are then cured to form patterned templates for use in soft or imprint lithography, allowing for the formation of micro- and nanoscale particles and patterns without scum layer formation, using materials like perfluoropolyether (PFPE) and other fluorinated polymers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If PDMS is used as the imprint lithography material, then the material offers flexibility and conformal contact, but it swells with organic solvents and reacts with acidic or basic solutions, leading to fidelity issues and scum layer formation
Solution Approach 1:
The patent changes the chemical composition parameters of the elastomeric material by incorporating fluorinated polymers (such as polytetrafluoroethylene or polyvinylidene fluoride) into the PDMS matrix. This compositional parameter change reduces surface energy and improves solvent resistance while maintaining the flexibility needed for conformal contact during imprint lithography
Solution Approach 2:
The patent creates a composite elastomeric material by combining PDMS with fluorinated polymers. This composite structure integrates the flexibility and conformal contact properties of PDMS with the solvent resistance and low surface energy of fluorinated polymers, resolving the contradiction between ease of operation and reliability
2Ease of operation
If PDMS is used as the imprint lithography material, then the material provides flexibility for release, but its high surface energy causes scum layer formation and poor release properties
Solution Approach 1:
The patent changes the surface energy parameter of the elastomeric material by incorporating fluorinated polymers, which have inherently low surface energy. This parameter change reduces adhesion between the elastomeric material and the imprinted layer, preventing scum layer formation and improving release properties
Solution Approach 2:
The patent converts the potential harm of high surface energy (which causes scum layer formation) into a benefit by using fluorinated polymers whose low surface energy property prevents adhesion issues. The low surface energy, which might seem to reduce bonding capability, actually benefits the release process by preventing unwanted adhesion
3Productivity
If traditional imprint lithographic techniques are used, then the process can manufacture micro- and nano-structures, but the materials swell with organic solvents and have high surface energy, making it difficult to fabricate isolated structures
Solution Approach 1:
The patent changes the surface energy and solvent resistance parameters of the elastomeric material through fluoropolymer incorporation. These parameter changes enable the material to maintain its structural integrity during imprinting while preventing scum layer formation, thus allowing fabrication of isolated micro- and nano-structures with high precision
Solution Approach 2:
The patent utilizes gas permeability of the fluorinated elastomeric material to facilitate solvent evaporation and prevent solvent trapping during the imprinting process. This pneumatic property helps maintain material stability and prevents swelling, enabling precise fabrication of isolated structures
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 method enables the fabrication of high-fidelity micro- and nanoscale structures and the delivery of therapeutic agents by preventing scum layer formation and enhancing the release properties of the materials, allowing for precise pattern placement and alignment, and improving the solvent resistance and flexibility of the templates.
Implementation Method 1
a patterned template formed by a replica molding process... casting low viscosity liquid materials onto a master template and then curing the low viscosity liquid materials
Data Source
AI summary
The presently disclosed subject matter describes the use of fluorinated elastomer-based materials, in particular perfluoropolyether (PFPE)-based materials, in high-resolution soft or imprint lithographic applications, such as micro- and nanoscale replica molding, and the first nano-contact molding of organic materials to generate high fidelity features using an elastomeric mold. Accordingly, the presently disclosed subject matter describes a method for producing free-standing, isolated nanostructures of any shape using soft or imprint lithography technique.