Core-Shell Porous Silica Particles Thick Shell Formation
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Solution Overview
Problem
Existing methods for producing core-shell porous silica particles struggle to achieve a sufficiently thick and stable shell while maintaining high separation efficiency and low liquid feeding resistance, particularly in applications like liquid chromatography.
Innovation Solution
A multi-stage process is employed to form a porous shell on non-porous silica particles, involving the use of a cationic surfactant, basic catalyst, and silica source in an aqueous solution, with repeated shell formation steps to increase shell thickness without compromising the pore structure or stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the particle size of the porous silica is increased to reduce liquid feeding resistance, then liquid feeding resistance decreases, but separation efficiency decreases due to longer release time
Solution Approach 1:
The particle is segmented into two functional zones: a non-porous silica core and a porous silica shell. The core provides structural support and determines particle size for low liquid feeding resistance, while the shell provides the porous structure for adsorption and separation, resolving the contradiction between particle size and separation efficiency
Solution Approach 2:
Different regions of the particle are given different properties: the core is non-porous with high density for structural integrity and low liquid feeding resistance, while the shell is porous with high surface area for adsorption and separation. This local differentiation allows each region to optimize its function without compromising the other
2Productivity
If the shell thickness is increased to improve separation efficiency, then separation efficiency increases, but production complexity increases requiring multiple repeated coating steps
Solution Approach 1:
The shell formation process is made continuous through repeated sequential coating steps where each step deposits additional porous silica layer on the previous shell. This continuous buildup approach allows precise control of shell thickness while maintaining process simplicity and avoiding the need for complex one-step thick-shell formation methods
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 results in core-shell porous silica particles with a significantly thicker and more stable shell, enhancing separation efficiency and reducing liquid feeding resistance, while maintaining a desired pore structure and cost-effectiveness.
Implementation Method 1
adding a silica source to the aqueous solution to form a shell precursor on a surface of the non-porous silica particle
Implementation Method 2
adding a silica source to the aqueous solution to form a shell precursor
Implementation Method 3
forming a shell precursor on a surface of the non-porous silica particle
Data Source
AI summary
An object of the present disclosure is to provide a method for producing a core-shell porous silica particle with an increased thickness of the shell. The object is met by a method for producing a core-shell porous silica particle, the method including the following steps: (a) preparing; (b) forming a shell precursor; (c) forming a shell; (d) preparing; (e) forming a shell precursor; and (f) forming a shell; wherein the steps (d) through (f) are further repeated one to three times, in which case the step of forming a shell described in step (d) refers to step (f).