Lewis Acid-Base Salt Microcapsules for Solvent-Free Encapsulation

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Solution Overview

Problem

Existing encapsulation methods often require ultrasonication and organic solvents, limiting their convenience and versatility in various technology areas, such as pharmaceutical and agricultural applications.

Innovation Solution

A method involving the formation of microcapsules using a reaction between a Lewis acid and a Lewis base reactant pair, where the reactants form a salt that precipitates at the droplet interface, encapsulating a water-immiscible core material without the need for complete solvation in the core phase, allowing for a wider variety of core materials and greater manufacturing flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If existing encapsulation methods are used, then encapsulation can be achieved, but ultrasonication and organic solvents are required which limits convenience and versatility

Engineering Contradiction:
Improveease of manufactureVSAvoidprocess complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent replaces mechanical ultrasonication with a chemical reaction system. Instead of using ultrasonic waves to emulsify and encapsulate materials, the invention uses a chemical reaction between wall-forming materials to form the encapsulating shell, eliminating the need for complex mechanical ultrasonication equipment and procedures.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental parameters of the encapsulation process by using aqueous solutions instead of organic solvents. The wall-forming reactants are dissolved in water rather than organic carriers, and the encapsulation is achieved through chemical reaction rather than mechanical energy input, fundamentally altering the process conditions to improve safety and versatility.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If conventional encapsulation methods are used, then microcapsules can be formed, but the process requires organic solvents which reduces versatility in various technology areas

Engineering Contradiction:
ImproveversatilityVSAvoiduse of organic solvents
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent creates an inert aqueous environment for the encapsulation process. By using water as the solvent system and forming the encapsulating wall through chemical reaction in this inert environment, the method eliminates the need for organic solvents, making the process safer and more versatile for different applications including pharmaceutical and agricultural uses.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

3Ease of manufacture

If the reactants form a salt that precipitates at the droplet interface, then encapsulation occurs without complete solvation in the core phase, but this requires precise control of the reaction

Engineering Contradiction:
Improvemanufacturing flexibilityVSAvoidreaction control
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The system is designed to be self-regulating. The wall-forming reactants automatically accumulate at the droplet interface through their amphiphilic nature, and the chemical reaction proceeds autonomously to form the encapsulating shell. This self-assembly mechanism eliminates the need for external control systems while maintaining precise encapsulation.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent uses amphiphilic wall-forming reactants as intermediaries that mediate between the aqueous phase and the water-immiscible core material. These intermediaries naturally accumulate at the interface and facilitate the chemical reaction that forms the encapsulating shell, enabling precise control without requiring complete solvation of the core material.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 provides robust, water-wettable microcapsules that prevent caking and enhance shelf life stability, with a ten to fifty percent increase in sedimentation volume, and allows for controlled release of active agents without breaking, offering improved ease of manufacturing and application.

Implementation Method 1

forming an emulsion including droplets of a water-immiscible core material in a first aqueous solution of an amphiphilic first wall-forming reactant that preferentially accumulates at the surface of the droplets

Methodology Applied
Scientific EffectAmphiphilic accumulation at interface: Amphiphiles

Implementation Method 2

combining the emulsion with the second aqueous solution to permit a reaction between the first and second reactants such that the resulting reaction product forms an encapsulating wall surrounding the core material of each emulsion droplet; wherein one of said first and second reactants includes a Lewis base reactant and the other includes a Lewis acid reactant, and wherein the reaction product consists of a salt of the Lewis base-Lewis acid reactant pair

Methodology Applied
Scientific EffectLewis acid-base reaction: Chemical Bonding

Implementation Method 3

the reactants form a salt that precipitates at the droplet interface, encapsulating a water-immiscible core material

Methodology Applied
Scientific EffectPrecipitation: Precipitation

Implementation Method 4

This method provides robust, water-wettable microcapsules that prevent caking and enhance shelf life stability

Methodology Applied
Scientific EffectWater-wettable surface effect: Wetting

Implementation Method 5

with a ten to fifty percent increase in sedimentation volume, and allows for controlled release of active agents without breaking

Methodology Applied
Scientific EffectVaporization: Evaporation

Implementation Method 6

allows for controlled release of active agents without breaking

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentUS8039015B2Microencapsulation product and process
Publication Date: 2011.10.18 SPEAKER TYCHO J

AI summary

Microcapsules possessing Lewis acid-Lewis base salt walls incorporate water-immiscible materials, such as N,N-diethyl-m-toluamide (DEET), as a core component. Such microcapsules, or similar microcapsules incorporating other core components, may be made by emulsifying a water-immiscible core component in an aqueous solution of one wall-forming reactant, such as the Lewis base, and then mixing that solution with the other wall-forming reactant, such as the Lewis acid. Various adjuvants may be included with the core component to contribute additional characteristics, such as enhancement of a controlled release characteristic or improved mechanical stability.