Reflecting Microcapsules with Ultrathin Shells for Precise Tracking

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Solution Overview

Problem

Existing methods for tracking fluid movements in both translational and rotational directions using microcapsules are limited by the deflection of light due to the material encapsulating the micro-mirrors, which hinders precise determination of the microcapsules' position and orientation.

Innovation Solution

A method involving interfacial polymerization between two liquid phases, where light-reflecting solid integral particles are dispersed in one phase and encapsulated within a thin, durable polymeric shell formed by polymerization at the interface, ensuring minimal light deflection and precise tracking of fluid movements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a thick polymeric shell is used to ensure durability and structural integrity of microcapsules, then the mechanical strength and stability are improved, but light deflection increases which reduces measurement precision

Engineering Contradiction:
Improvestructural integrityVSAvoidposition and orientation determination
Core Design Contradiction:
StrengthVSMeasurement precision

Solution Approach 1:

The patent applies this principle by forming an ultrathin polymeric shell (10-100 nm thickness) through interfacial polymerization that provides structural integrity while being optically transparent. The thin film approach allows the shell to maintain mechanical strength and stability without deflecting light, thus enabling precise tracking of microcapsule position and orientation.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent changes the thickness parameter of the polymeric shell from conventional thick shells to ultrathin shells (10-100 nm). This parameter change resolves the contradiction by making the shell thin enough to be optically transparent while still providing sufficient structural integrity through the polymeric material properties and interfacial polymerization process.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If the polymeric shell is made thin to reduce light deflection, then measurement precision is improved, but the durability and structural integrity may be compromised

Engineering Contradiction:
Improveposition and orientation determinationVSAvoidstructural integrity
Core Design Contradiction:
Measurement precisionVSStrength

Solution Approach 1:

The patent employs ultrathin polymeric films (10-100 nm) formed by interfacial polymerization that achieve both optical transparency and mechanical durability. The thin film structure minimizes light deflection for precise tracking while the polymeric cross-linked network provides sufficient structural integrity to protect the microcapsule contents.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent creates a composite structure with a polymeric shell formed by interfacial polymerization between two immiscible liquid phases. This composite approach combines the benefits of thin film transparency with the mechanical strength of cross-linked polymeric networks, achieving both optical and mechanical requirements simultaneously.

Inventive Principle:
Principle #40Composite materials

3Ease of manufacture

If conventional microcapsule production methods are used, then manufacturing complexity is reduced, but the shell thickness cannot be controlled to be thin enough for optical transparency

Engineering Contradiction:
Improveproduction simplicityVSAvoidshell thickness control
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent uses an interfacial polymerization process where two immiscible liquid phases are combined, and the polymeric shell forms at the liquid-liquid interface. This hydraulic approach allows precise control of shell thickness (10-100 nm) by controlling the polymerization conditions while maintaining relative manufacturing simplicity through continuous phase mixing.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The patent changes the manufacturing approach from conventional single-phase or coacervation methods to interfacial polymerization between two immiscible liquid phases. This parameter change in the production method enables precise control of shell thickness at the nanometer scale while maintaining ease of manufacture through continuous flow processing.

Inventive Principle:
Principle #35Parameter changes

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 method produces spherical microcapsules with thin, durable shells that do not deflect light, allowing for accurate determination of their position and orientation, even in transparent fluids, with high yield and structural integrity, enabling faithful tracking of fluid movements.

Implementation Method 1

The droplets are then immersed in the second liquid phase under the polymerization conditions. This results in the first polymerization partner and the second polymerization partner polymerizing at the surfaces of the droplets and thus forming shells of a polymeric material enclosing the individual droplets.

Methodology Applied
Scientific EffectInterfacial polymerization: Chemical Bonding

Data Source

PatentEP3212321B1Reflecting spherical microcapsules and methods of their production
Publication Date: 2020.06.24 MAX PLANCK GESELLSCHAFT ZUR FOERDERUNG DER WISSENSCHAFTEN EV
  • EP3212321B1 patent drawingFigure 1
  • EP3212321B1 patent drawingFigure 2
  • EP3212321B1 patent drawingFigure 3

AI summary

Spherical microcapsules including light reflecting solid integral particles reflecting incoming light to be reflected in a defined direction for determining the position and orientation of the microcapsule are produced by (6) preparing a first liquid phase containing a first polymerization partner; (10) preparing a second liquid phase containing a second polymerization partner, the first liquid phase not being soluble in the second liquid phase, and the second polymerization partner being configured to polymerize with the first polymerization partner under polymerization conditions; (7) dispersing the solid particles in the first liquid phase; (8) forming droplets of the first liquid phase including at least one of the solid particles; and (9) immersing the droplets in the second liquid phase under the polymerization conditions, wherein the first polymerization partner and the second polymerization partner polymerize at the surfaces of the droplets forming shells of a polymeric material enclosing the individual droplets, and wherein the light reflecting solid integral particles are fixed to the shells.