Double-Shell Silica Microcapsule Encapsulation Stability
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Solution Overview
Problem
Existing methods for producing silica microcapsules struggle to achieve high encapsulation rates of organic compounds like fragrances due to the brittleness and thinness of the silica shells, leading to leakage and reduced stability.
Innovation Solution
A method involving a sol-gel reaction process where an emulsion of an organic compound and a silica source is subjected to acidic conditions to form a first silica shell, followed by the addition of an anionic surfactant and further sol-gel reaction to create a denser and more sturdy second shell, enhancing encapsulation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single silica shell is formed through sol-gel reaction, then the microcapsule structure is simple, but the encapsulation stability is insufficient due to shell brittleness and thinness
Solution Approach 1:
The patent applies nested doll principle by forming a double-shell structure where an inner silica shell encloses the organic compound core, and an outer silica shell encloses the inner shell. This nested configuration provides enhanced protection and stability while maintaining reasonable structural complexity, directly resolving the contradiction between simple structure and sufficient encapsulation stability.
Solution Approach 2:
The patent employs composite materials principle by creating a multi-layered microcapsule system combining organic compound core with dual silica shells. The composite structure of organic core enclosed by inorganic silica layers provides superior mechanical strength and encapsulation stability compared to single-shell structures, addressing the reliability issue while managing complexity.
2Quantity of substance
If the silica shell is made thin to reduce material usage, then the manufacturing cost decreases, but the shell becomes more brittle and prone to collapse
Solution Approach 1:
The nested double-shell structure allows each individual silica shell to maintain optimal thickness for strength while the combined nested configuration provides overall enhanced protection. The inner shell can be thin for material efficiency, while the outer shell provides additional structural support, resolving the contradiction between material quantity and shell strength.
Solution Approach 2:
The outer silica shell acts as a protective cushion that prevents direct collapse or damage to the inner shell containing the organic compound. This beforehand cushioning effect ensures that even if the inner shell is thin, the overall microcapsule maintains sufficient strength and protection, addressing the strength concern while allowing material 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 method effectively stabilizes the encapsulation of organic compounds within silica microcapsules, achieving a high encapsulation rate and maintaining the integrity of the encapsulated fragrance even after filtration processes.
Implementation Method 1
subjecting an emulsion obtained by emulsifying an aqueous phase component comprising a cationic surfactant, and an oil phase component comprising at least one organic compound and a silica source to a sol-gel reaction under an acidic condition
Implementation Method 2
performing a sol-gel reaction under an acidic condition to form a silica microcapsule
Data Source
AI summary
The present invention relates to a method of producing a microcapsule that includes a shell containing silica as a constituent component and a core containing at least one organic compound inside the shell. The production method of the microcapsule includes: step 1: obtaining a water dispersion of a silica microcapsule (1) containing an organic compound, and step 2: adding an anionic surfactant to the water dispersion obtained in the step 1, and then performing a sol-gel reaction in the presence of a silica source to form a microcapsule having a shell that encloses the silica microcapsule (1).