Substrate Surface Energy Control via Homopolymer Mixtures
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Solution Overview
Problem
Current methods for controlling the surface energy of substrates to orient block copolymer nano-domains perpendicular to the surface are complex, tedious, and not industrially feasible due to difficulties in synthesizing copolymers with precise co-monomer ratios and the need for multiple experimental parameters.
Innovation Solution
A process involving a mixture of polymers with grafting or crosslinking functions, allowing precise control of surface energy by mixing polymers of known compositions and treating the substrate to achieve the desired orientation of block copolymer nano-domains, reducing the number of necessary syntheses and experimental errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a random copolymer is deposited on the substrate to control surface energy, then the orientation of nano-domains perpendicular to the surface is improved, but the complexity of synthesizing copolymers with precise co-monomer ratios increases
Solution Approach 1:
The patent divides the copolymer system into separate homopolymer components. Instead of synthesizing a single random copolymer with precise co-monomer ratios, the invention uses mixtures of homopolymers (e.g., PMMA and PS) that can be independently synthesized and then combined. This segmentation simplifies the synthesis process while maintaining the ability to control surface energy and achieve perpendicular nano-domain orientation.
Solution Approach 2:
The patent employs composite material strategies by creating surfaces functionalized with mixtures of homopolymers. These composite surfaces combine the properties of different homopolymers to achieve the desired surface energy characteristics. The composite approach allows flexible adjustment of composition ratios without the complexity of copolymer synthesis, enabling precise control over block copolymer orientation.
2Reliability
If crosslinking is performed on the copolymer to prevent diffusion, then the stability of the surface treatment is improved, but the ability to remove excess copolymer is reduced
Solution Approach 1:
The patent applies preliminary action by performing crosslinking only after the block copolymer has been deposited and self-assembled on the surface. The crosslinking step is executed as a final stabilization step, not before deposition. This timing allows excess uncrosslinked copolymer to be easily removed by solvent washing before the crosslinking occurs, while still achieving the desired stability and orientation control after crosslinking.
3Manufacturing precision
If the composition of random copolymer is varied to achieve neutral surface, then the orientation control is improved, but the difficulty of finding precise co-monomer ratios increases
Solution Approach 1:
The patent applies parameter changes by transitioning from controlling copolymer composition (co-monomer ratios) to controlling homopolymer mixture ratios. Instead of synthesizing copolymers with precise co-monomer compositions, the invention varies the proportions of pre-synthesized homopolymers in the mixture. This parameter change simplifies the control process, as homopolymer ratios can be easily adjusted and measured without complex synthesis optimization.
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 allows for easy and precise control of surface energy, enabling the orientation of block copolymer nano-domains perpendicular to the surface, facilitating the generation of nano-structured patterns with improved reproducibility and reduced costs.
Implementation Method 1
each copolymer comprising at least one function allowing its grafting or crosslinking on the surface of said substrate
Implementation Method 2
each copolymer comprising at least one function allowing its grafting or crosslinking on the surface of said substrate
Implementation Method 3
by phase segregation between the blocks thus forming nano-domains
Implementation Method 4
an annealing step allowing a nano-structuring of said block copolymer by generation of nano-structured patterns oriented in a particular direction
Data Source
Figure 1~2
AI summary
The invention relates to a method for controlling the surface energy of a substrate, so as to obtain a specific orientation of the nanodomains of a block copolymer film deposited subsequently on the surface, said method being characterised in that it comprises the following steps of: preparing a mixture of polymers, each polymer comprising at least one functional group allowing same to be grafted or crosslinked to the surface of the substrate; depositing the mixture thus prepared on the surface of the substrate; performing a treatment resulting in the grafting or crosslinking of each of the polymers of the mixture to the surface of the substrate.