Microcapsule Volatile Release Assessment Using Shear Stress
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Solution Overview
Problem
Existing methods for assessing the release performance of microcapsules, such as the indentation method, fail to accurately predict the mechanical behavior of core-shell microcapsules under real-life conditions due to unrealistic stress directions and substrate deformation, leading to underestimation of fracture strength and poor correlation with olfactive performance.
Innovation Solution
A method involving the application of kinetic frictional shear stress to microcapsules under defined load, contact surface area, and shear rate using a tribometer, which mimics real-life deformations and allows for the measurement of volatile ingredient release, providing a more accurate assessment of microcapsule performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the indentation method is used to measure fracture strength, then the measurement can be performed on a hard substrate surface, but the fracture strength is significantly under-estimated due to substrate deformation effects
Solution Approach 1:
The invention creates a simplified copy of the real-life mechanical environment by using a soft substrate that mimics the deformable characteristics of fabrics, hair, and skin. This allows the indentation method to be performed under conditions that replicate actual application scenarios, thereby improving the reliability of fracture strength predictions without requiring complex real-world testing setups.
Solution Approach 2:
The invention changes the substrate parameter from hard/rigid to soft/deformable, matching the mechanical properties of real-world substrates. This parameter change ensures that the substrate deformation behavior during indentation reflects actual application conditions, correcting the under-estimation of fracture strength that occurs with hard substrates.
2Device complexity
If the indentation method measures rupture force perpendicular to a hard substrate surface, then the measurement setup is simple, but the stress direction does not represent real-life conditions where shear components are present
Solution Approach 1:
The invention changes the substrate mechanical parameter to be soft and deformable, which enables the indentation process to generate realistic shear stress components while maintaining the simplicity of the measurement setup. The soft substrate deforms during indentation, naturally creating the complex stress state with shear components that characterizes real-life conditions.
3Use of energy by moving object
If microcapsules are tested on a hard substrate surface, then the energy is dissipated only in deforming the microcapsule, but this does not reflect real substrates like fabrics and skin that are deformable
Solution Approach 1:
The invention uses a soft substrate that copies the energy absorption characteristics of real-world substrates like fabrics and skin. During indentation, the soft substrate deforms and absorbs a portion of the applied energy, replicating the energy dissipation mechanism that occurs in actual applications. This leads to more accurate fracture strength measurements that correlate with olfactive performance.
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 effectively correlates the release of volatile ingredients with olfactive performance scores, offering a practical alternative to existing methods by accurately simulating the deformations microcapsules experience in real-life applications and guiding the development of high-performing microcapsules.
Implementation Method 1
applying a kinetic frictional shear stress through a contact surface of a probe under a predefined load p, a predefined contact surface area and a predefined shear rate to said plurality of microcapsules
Implementation Method 2
measuring the amount of the at least one volatile ingredient released per second from said microcapsules under said kinetic frictional shear stress
Implementation Method 3
the amount of volatile ingredients released from the microcapsules correlates in a most satisfactory manner to the microcapsule olfactive performance score
Data Source
AI summary
A method for assessing the release performance of microcapsules comprising at least one volatile ingredient, the method comprising the steps of:a. applying a plurality of said microcapsules to an underlying surface;b. applying a kinetic frictional shear stress τ through a contact surface of a probe under a predefined load, a predefined contact surface area and a predefined shear rate to said plurality of microcapsules; andc. measuring the amount of the at least one volatile ingredient released per second from said microcapsules under said kinetic frictional shear stress τ.