pH-Tunable Microcapsule Shell via Diester Diacid Chloride and Polyamine

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Solution Overview

Problem

Existing microcapsule technologies lack the ability to achieve pH-triggered release of hydrophobic liquids across a wide pH range without requiring different encapsulation or triggered release strategies, with most systems only effective at either high or low pH environments.

Innovation Solution

Microcapsule compositions with a core of hydrophobic liquid and a shell formed from the reaction product of simple diester diacid chloride monomers and polyamines, such as pyromellitic diester diacid chloride and N,N′,N″-tris(2-aminoethyl)-1,3,5-triazine-2,4,6-triamine, which allow for pH-tunable release in both high and low pH environments by interfacial polymerization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional microcapsule systems are used, then they can provide release at specific pH conditions, but they cannot achieve pH-triggered release across a wide pH range without requiring different encapsulation strategies

Engineering Contradiction:
ImprovepH range for triggered releaseVSAvoidnumber of different encapsulation strategies
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The microcapsule shell is designed with dual functionality to respond to both high pH (≥9) and low pH (≤6) environments using a single encapsulation chemistry. The shell comprises the reaction product of at least one simple diester diacid chloride monomer and at least one polyamine, creating a system that can trigger release across the entire pH spectrum without requiring different encapsulation strategies for different pH conditions.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention utilizes pH as a critical parameter to control the degradation and release behavior of the microcapsule shell. By designing the shell chemistry to be sensitive to pH changes, the system achieves triggered release at different pH levels (high pH ≥9, neutral pH 7-8, low pH ≤6) through the same encapsulation structure, eliminating the need for multiple specialized systems.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If pH-triggered release is achieved, then release can be controlled at desired pH conditions, but the shell may become unstable or leak in non-polar environments

Engineering Contradiction:
Improverelease control at pH conditionsVSAvoidshell stability in non-polar environments
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The microcapsule structure is designed with differentiated properties for different environments. The shell comprises the reaction product of at least one simple diester diacid chloride monomer and at least one polyamine, creating a composition that provides stability in non-polar environments while maintaining pH-triggered release capability in aqueous environments. This local quality differentiation allows the shell to exhibit environment-specific behavior.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The shell is formed as a composite material through the reaction of diester diacid chloride monomers with polyamines. This composite structure provides both the stability needed to prevent leakage in non-polar environments and the pH-sensitivity required for controlled release in aqueous environments at different pH levels.

Inventive Principle:
Principle #40Composite materials

3Quantity of substance

If thin-shell microcapsules are used to increase capacity, then encapsulation capacity increases, but barrier properties and controlled release may be compromised

Engineering Contradiction:
Improveencapsulation capacityVSAvoidbarrier properties and controlled release
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The invention employs thin-shell microcapsules formed from the reaction product of simple diester diacid chloride monomers and polyamines. This thin shell design increases encapsulation capacity while the specific chemistry provides sufficient barrier properties and controlled release functionality. The shell thickness is optimized to balance capacity with the ability to maintain barrier properties and enable pH-triggered release.

Inventive Principle:
Principle #30Flexible shells and thin films

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

The microcapsules demonstrate resistance to leakage in non-polar environments and enable pH-tunable release of hydrophobic liquids, allowing the same chemistry to be used in various pH conditions without changing encapsulation strategies, with sustained release at neutral pH and accelerated release at high and low pH.

Implementation Method 1

the shell comprises the reaction product of at least one simple diester diacid chloride monomer and at least one polyamine... placing a microcapsule composition... into an aqueous environment having a pH of 9 or greater... placing a microcapsule composition... into an aqueous environment having a pH of 6 or less

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Data Source

PatentUS10405543B2Microcapsule compositions and the method of their release
Publication Date: 2019.09.10 NUTRITION & BIOSCIENCES USA 2 LLC

AI summary

The present invention provides microcapsules with good barrier properties and the ability to release encapsulated hydrophobic liquids at low and high pH.