Light-Triggered Microcapsule Release via Carbon Nanotube Photothermal Rupture

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Solution Overview

Problem

Existing microcapsules lack a reliable mechanism for remote-controlled release of chemicals, as they typically require mechanical stress or electric potential for content release, and light-triggered release is not common for free-flowing microcapsules, especially with carbon nanotubes which are poorly soluble in organic solvents.

Innovation Solution

Development of microcapsules with a polyamide shell containing a chemically reactive material and carbon nanotubes, where the carbon nanotubes absorb light and generate heat to rupture the shell, allowing for remote, light-triggered release of encapsulated chemicals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If carbon nanotubes are used as light absorbing material in microcapsules, then light-triggered release capability is improved, but solubility in organic solvents deteriorates

Engineering Contradiction:

Improvelight-triggered release capabilityVSAvoidsolubility in organic solvents

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent uses an emulsion system as an intermediary medium during manufacturing. Carbon nanotubes are first dispersed in an aqueous phase containing surfactants, then this dispersion is emulsified with organic solution containing the encapsulated material. The emulsion acts as a bridge that allows carbon nanotubes to be incorporated into the microcapsule shell without requiring direct solubility in the organic phase, thus resolving the solubility contradiction.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the physical and chemical parameters of the carbon nanotube dispersion by adjusting pH, ionic strength, and surfactant concentration in the aqueous phase. These parameter changes optimize the dispersion stability and surface properties of carbon nanotubes, enabling them to be effectively incorporated into the microcapsule shell structure while maintaining their light-absorbing properties.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If interfacial polymerization is used to form polyamide shell, then shell formation reliability is improved, but manufacturing complexity increases

Engineering Contradiction:

Improveshell formation reliabilityVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent performs preliminary dispersion of carbon nanotubes in the aqueous phase before the interfacial polymerization reaction. This preliminary action ensures that carbon nanotubes are uniformly distributed and properly surface-modified before shell formation begins, which improves the reliability of shell formation and ensures consistent incorporation of light-absorbing material throughout the shell structure.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent merges multiple functions into the interfacial polymerization step: shell formation, incorporation of carbon nanotubes, and encapsulation of the organic material all occur simultaneously during the polymerization reaction. This combining of operations reduces the overall number of separate manufacturing steps and simplifies the process while maintaining reliable shell formation.

Inventive Principle:

Principle #5Merging (Combining)

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 provide stable packaging and remote control release of chemicals, maintaining encapsulated liquid integrity until triggered by light, achieving efficient release with high precision and compatibility with various solvents and environments.

Implementation Method 1

Carbon nanotubes (CNTs) absorb light across the entire spectrum

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

efficiently convert the absorbed light into heat

Methodology Applied

Scientific EffectPhotothermal conversion:

Implementation Method 3

The interfacial polymerization of triamines and diacid or triacid chlorides in an oil-in-water emulsion

Methodology Applied

Scientific EffectInterfacial polymerization:

Data Source

PatentUS8822618B2Microcapsule and methods of making and using microcapsules

Publication Date: 2014.09.02 RGT UNIV OF CALIFORNIA

AI summary

An embodiment of a microcapsule includes a shell surrounding a space, a liquid within the shell, and a light absorbing material within the liquid. An embodiment of a method of making microcapsules includes forming a mixture of a light absorbing material and an organic solution. An emulsion of the mixture and an aqueous solution is then formed. A polymerization agent is added to the emulsion, which causes microcapsules to be formed. Each microcapsule includes a shell surrounding a space, a liquid within the shell, and light absorbing material within the liquid. An embodiment of a method of using microcapsules includes providing phototriggerable microcapsules within a bulk material. Each of the phototriggerable microcapsules includes a shell surrounding a space, a chemically reactive material within the shell, and a light absorbing material within the shell. At least some of the phototriggerable microcapsules are exposed to light, which causes the chemically reactive material to release from the shell and to come into contact with bulk material.