Controlled Liquid Jet Dosing for Receding Contact Angle Measurement

Solution Overview

Problem

Existing methods for measuring contact angles, particularly receding contact angles, are difficult and unreliable due to factors such as surface roughness, chemical inhomogeneities, and the dynamic nature of wetting and de-wetting processes, leading to inconsistent and time-consuming measurements.

Innovation Solution

A method and apparatus that form a drop on a surface using a continuous liquid jet with controlled flow rate and dosing time to ensure the initial wetted area is larger than the equilibrium area, allowing for the formation of a receding contact angle, using a dosing volume limited by the formula Vmax = 0.11 s * flux, enabling rapid and reliable measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a liquid drop is applied to a sample surface using conventional methods (cannula or liquid needle), then the contact angle measurement can be performed, but the measurement process is time-consuming and results are inconsistent due to surface roughness, chemical inhomogeneities, and wetting dynamics

Engineering Contradiction:

Improvecontact angle measurement precisionVSAvoidmeasurement time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The invention changes the dosing parameters by strictly controlling the dosing volume to not exceed the flow rate multiplied by 0.11 seconds. This parameter change ensures that the initial wetted area is sufficiently large compared to the equilibrium area, enabling reliable receding contact angle measurements and reducing measurement time from minutes to seconds

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention performs preliminary action by ensuring the liquid is applied as a continuous jet with controlled dosing volume before the measurement process begins. This preliminary control of dosing parameters prepares the optimal initial conditions for rapid and consistent receding contact angle measurement

Inventive Principle:

Principle #10Preliminary action

2Productivity

If the liquid is applied as a continuous jet with high flow rate, then the measurement speed increases, but the dosing volume may exceed the optimal limit, preventing proper receding contact angle formation

Engineering Contradiction:

Improvemeasurement speedVSAvoiddosing volume control precision

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The invention changes the dosing parameters by strictly controlling the dosing volume to not exceed the flow rate multiplied by 0.11 seconds. This parameter change ensures that the initial wetted area is sufficiently large compared to the equilibrium area, enabling reliable receding contact angle measurements and reducing measurement time from minutes to seconds

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention implements feedback control by monitoring and adjusting the dosing volume based on the flow rate. The dosing time is controlled to ensure the dosing volume remains within the optimal limit (flow rate × 0.11 s), allowing the system to maintain both high speed and high precision across varying flow conditions

Inventive Principle:

Principle #23Feedback

3Reliability

If the dosing volume is increased to ensure adequate wetting area, then the initial wetted area is sufficient for receding contact angle formation, but the measurement becomes less reliable due to excessive volume affecting drop shape and equilibrium

Engineering Contradiction:

Improvereceding contact angle measurement reliabilityVSAvoiddosing volume

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The invention changes the dosing parameters by strictly controlling the dosing volume to not exceed the flow rate multiplied by 0.11 seconds. This parameter change ensures that the initial wetted area is sufficiently large compared to the equilibrium area, enabling reliable receding contact angle measurements and reducing measurement time from minutes to seconds

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

Enables fast and automated measurement of receding contact angles with high precision, reducing measurement time from minutes to seconds and providing consistent results across various liquid and surface combinations.

Implementation Method 1

the interaction of the surface and the liquid also depends on the wetting dynamics

Methodology Applied

Scientific EffectWetting: Wetting

Data Source

PatentUS12360030B2Method and apparatus for measuring a receding contact angle

Publication Date: 2025.07.15 KRUSS

AI summary

A method for measuring a receding contact angle between a sample surface and a drop of a liquid is provided. The method includes ejecting a dosing volume of the liquid from an opening onto the sample surface such that the liquid is ejected as a continuous jet at a defined flow rate for a defined dosing time period, and the opening comprises an opening diameter. The dosing volume of the liquid is allowed to form a drop on the sample surface. At least one geometrical parameter of the drop formed on the sample surface is measured and a contact angle between the sample surface and the drop is determined based on the at least one geometrical parameter. The flow rate and the dosing time period are selected such that the dosing volume does not exceed the flow rate multiplied by 0.11 s.