Rotating Drop Interfacial Tension Measurement
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Solution Overview
Problem
Current methods for measuring interfacial tension between heavier and lighter liquids using the spinning drop method face challenges such as turbulence, adhesion of the lighter liquid to the sample vessel walls, and prolonged establishment of a stable state, especially at low interfacial tensions or small density differences, leading to unreliable measurements.
Innovation Solution
A method involving a transparent sample vessel with a stopper that has a receptacle for the lighter liquid, where the liquids are introduced such that the lighter liquid is initially placed in the receptacle, and the vessel is rotated at a first speed before reducing to a second speed to facilitate the formation of an elongated droplet at the center, preventing adhesion and turbulence, allowing for precise optical measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the lighter liquid is introduced directly into the sample vessel using a syringe with a cannula, then the liquid can be introduced efficiently, but turbulence occurs leading to droplet formation and adhesion to the vessel wall
Solution Approach 1:
The invention divides the liquid introduction process into two separate stages: first introducing the lighter liquid into the stopper's receptacle, then introducing the heavier liquid into the sample vessel. This segmentation prevents direct contact between the cannula and the lighter liquid, eliminating turbulence and adhesion issues while maintaining efficient introduction through the same cannula system.
Solution Approach 2:
The stopper's receptacle serves as an intermediary container for the lighter liquid. Instead of introducing the lighter liquid directly into the sample vessel where it would cause turbulence, the receptacle holds the lighter liquid and allows it to be transferred smoothly to the sample vessel through the opening, preventing harmful direct introduction.
2Ease of operation
If the lighter liquid adheres to the glass tube wall, then it can be introduced into the sample vessel, but parts of the liquid separate and form multiple droplets impairing optical measurement
Solution Approach 1:
The invention performs preliminary action by introducing the lighter liquid into the stopper's receptacle before introducing the heavier liquid into the sample vessel. This preliminary placement in the receptacle allows the lighter liquid to be positioned correctly and transferred smoothly, preventing adhesion to the glass wall and subsequent droplet formation that would impair optical measurement.
3Stability of the object's composition
If strong turbulence occurs during liquid introduction, then the liquids can be mixed, but an emulsion forms and stable state establishment takes very long time
Solution Approach 1:
The invention applies preliminary anti-action by preventing turbulence from occurring in the first place. By introducing the lighter liquid into the stopper's receptacle first and then introducing the heavier liquid into the sample vessel through the same opening, the method prevents the strong turbulence that would otherwise occur during direct syringe introduction, thereby avoiding emulsion formation and the lengthy time required to establish a stable state.
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 approach simplifies sample preparation, reduces measurement time, and ensures accurate determination of interfacial tension by preventing lighter liquid adhesion to the vessel walls and minimizing turbulence, enabling reliable and efficient measurement of interfacial tension.
Implementation Method 1
the lighter liquid is conveyed out of the receptacle of the stopper and is transported from receptacle and stopper in the direction of the center of the sample vessel
Data Source
Figure 1~4
Figure 5~8
AI summary
Method for measuring interfacial tension between a heavier liquid and a lighter liquid comprising the following steps: • Providing a transparent sample vessel having an interior and an opening, • Providing a stopper that can close the opening and has a receptacle for the lighter liquid, • Introducing the heavier liquid into the transparent sample vessel, • Introducing the lighter liquid into the receptacle of the stopper, • Closing the opening of the transparent sample vessel with the stopper so that the receptacle of the stopper faces the interior of the transparent sample vessel, • Setting the transparent sample vessel into a rotational motion about its longitudinal axis at a first speed, • Decreasing the speed of the rotational motion from the first speed to a second speed.• Measuring a geometric property of an elongated droplet of the lighter liquid that is completely surrounded by the heavier liquid.