Solvent Shifting Nanoparticle Dispersion via Membrane Filtration
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Solution Overview
Problem
Existing methods fail to maintain stability and dispersion of cerium dioxide nanoparticles when transferring them from an aqueous, polar environment to a non-polar medium, such as diesel fuel, leading to agglomeration and loss of desirable properties.
Innovation Solution
Employing semi-permeable membrane filtration to remove the continuous aqueous phase and introduce a less polar solvent, allowing for efficient solvent shifting and maintaining a stable, homogeneous dispersion of nanoparticles in a non-polar medium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If particle stabilizers are used to prevent particle agglomeration in aqueous environment, then particle stability in polar medium is improved, but particle stability in non-polar medium deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the stabilizer from purely polar groups to a combination of polar and non-polar groups. This parameter change allows the stabilizer to function in both polar and non-polar solvents, resolving the contradiction between particle stability in aqueous environment and adaptability to non-polar media.
Solution Approach 2:
The patent employs composite stabilizer molecules that combine both polar and non-polar functional groups in a single structure. This composite approach allows the stabilizer to simultaneously interact with polar surfaces (e.g., metal oxides) and non-polar solvents, enabling particle stability across different solvent types without requiring separate stabilizers for each environment.
2Stability of the object's composition
If conventional stabilizers are replaced with new stabilizers having different affinity, then particle stability in non-polar medium is improved, but process complexity increases
Solution Approach 1:
The patent develops a universal stabilizer that performs multiple functions: it stabilizes particles in both polar and non-polar media, eliminates the need for separate displacement reactions, and removes the requirement for isolation and re-dispersal steps. This multi-functionality significantly simplifies the overall process while maintaining particle stability across different solvent environments.
Solution Approach 2:
The patent extracts the problematic intermediate steps (displacement reactions, isolation, re-dispersal) from the stabilization process by using a stabilizer that works directly in the target non-polar medium. This extraction of unnecessary process steps reduces complexity while achieving the same or better particle stability.
3Loss of time
If particles are transferred directly from aqueous to non-polar solvent, then process time is reduced, but particle agglomeration occurs
Solution Approach 1:
The patent applies preliminary action by pre-equipping particles with dual-affinity stabilizers before transfer. This preliminary stabilization ensures that particles are immediately protected upon contact with non-polar solvent, preventing agglomeration during the direct transfer process and eliminating the need for intermediate stabilization steps.
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 transfer of cerium dioxide nanoparticles into a non-polar medium while preserving their stability and properties, eliminating the need for changing stabilizers and reducing the complexity of the process.
Implementation Method 1
Dialysis and diafiltration methods have been employed to purify biological materials by replacing minor amounts of organic solvents, organic surfactants, reaction by-products and salts, with water in order to reduce the toxicity of the final material.
Implementation Method 2
In dialysis, an aqueous solution or particle dispersion to be purified is placed into a dialysis bag (internal phase), and typically suspended in an aqueous (external phase) bath, from which water diffuses into the bag while salts diffuse out through holes in the semi-permeable dialysis membrane, driven only by concentration gradients (osmosis).
Data Source
AI summary
A process for replacing the continuous phase of a nanoparticle dispersion with a less polar phase, includes filtering the dispersion through a semi-permeable membrane filter to remove the continuous phase, and introducing a less polar phase.