Persistent micelle corona chemistry
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Solution Overview
Problem
Existing methods struggle to independently control the size and functionalization of micelles, which are crucial for various applications due to reliance on equilibrium-based processing and dynamic chain exchange mechanisms.
Innovation Solution
A method involving dissolving a block copolymer in a first solvent to form a dispersion, followed by contact with a second selective solvent, and removing the first solvent via evaporation to create persistent micelles with immobilized core blocks, allowing for kinetic entrapment and independent adjustment of functional group density and Coulombic interaction strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If equilibrium-based processing is used to form micelles, then micelles can form dynamically, but the aggregation number and functionalization cannot be independently controlled
Solution Approach 1:
The patent changes the solvent quality parameter to induce micellization. By using a selective solvent that is good for the corona block but poor for the core block, the system transitions from unimers to micelles. This parameter change allows kinetic trapping of micelles with specific aggregation numbers, enabling independent control of both aggregation number and functionalization.
Solution Approach 2:
The patent exploits the dynamic nature of micelle formation and stabilization processes. During micellization, chains dynamically exchange between unimers and micelles. By controlling the solvent quality and using high-χN conditions, the system transitions from dynamic equilibrium to kinetic trapping, where micelles become persistent with fixed aggregation numbers.
2Adaptability or versatility
If dynamic chain exchange processes occur, then micelles can adapt to environmental changes, but the micelle size cannot be kinetically trapped
Solution Approach 1:
The patent uses high-χN conditions (high Flory-Huggins interaction parameter times degree of polymerization) to change the thermodynamic barrier for chain exchange. This parameter change kinetically traps the micelles, preventing chain exchange and fixing the micelle size, while still allowing environmental response through corona block functional groups.
3Manufacturing precision
If high-χN conditions are used to kinetically trap micelles, then micelle size can be controlled, but chemical modifications of the corona become difficult
Solution Approach 1:
The patent performs chemical modifications of the corona block before micellization occurs. By functionalizing the polymer chains while they are still in the unimer state (in a good solvent), the modifications are easily introduced. Subsequently, when the selective solvent is added and micelles form, the functional groups are already in place on the corona blocks, allowing size control without compromising modification ease.
4Stability of the object's composition
If block copolymer micelles undergo single chain exchange, then micelles can reach equilibrium, but the process has high rate dependence on χN creating kinetic barriers
Solution Approach 1:
The patent uses high-χN conditions to dramatically slow down the single chain exchange rate. The double exponential rate dependence on χN means that increasing χN creates a large thermodynamic activation energy barrier, effectively freezing the micelle aggregation number and creating persistent micelles with fixed compositions.
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 maintains a constant core size while enabling independent tailoring of functional group density and Coulombic interactions, resulting in persistent micelles with controlled properties suitable for diverse applications.
Implementation Method 1
dissolving a block copolymer in a first solvent to form a dispersion containing unimers or dynamic micelles
Implementation Method 2
removing the first solvent via evaporation to create persistent micelles with immobilized core blocks
Data Source
AI summary
A method of forming persistent micelles is described. Particularly, methods disclosed herein include dissolving a block copolymer in a first solvent to form a dispersion containing unimers or dynamic micelles. Further, a method includes contacting the dispersion with a second solvent forming the persistent micelles. The persistent micelles formed by the method of the present disclosure can be used for controlled delivery of dispersions in organic electronic coatings, paint, or drug delivery applications and can also be used to control the pore size of films that include an oxide, a nitride, a carbide, a metal, or a carbon material.