Algorithms and Validation Data for Multi‑Technique Contact Angle Measurements

Algorithms and Validation Data for Multi‑Technique Contact Angle Measurements under Pressure and Temperature Control

Overview

This dataset contains the algorithmic tools, validation data, and example workflows used to determine apparent contact angles through image‑based processing methods. It supports the development, verification, and reproducibility of a multi‑technique experimental system capable of measuring contact angles under controlled pressure and temperature conditions (Tapias‑Boon System).

The dataset includes synthetic droplet generation tools, image‑processing algorithms for multiple measurement techniques, statistical validation results, example images, and documentation for all MATLAB scripts. All resources are organized to facilitate reproducibility, benchmarking, and integration into experimental workflows.

1. SmartDroplet Toolkit

The SmartDroplet Toolkit provides MATLAB‑based tools for generating synthetic droplet contours, processing droplet shapes, and validating contact angle algorithms.

1.1 Synthetic Droplet Contour Generator

Generates idealized droplet contours across a user‑defined contact‑angle range.
Supports both random and predefined angle generation.
Enables systematic algorithm validation.

1.2 Droplet Contour Processing Tools

Automated contour extraction in hydrophilic and hydrophobic regimes.
Contact‑point detection using cross‑product slope analysis.
Parabolic fitting for precise angle estimation.
Interactive visualization utilities.

1.3 Statistical Validation Suite

Scatter plots: measured vs. true angles.
PDF of absolute error: distribution of measurement deviations.
Bland–Altman analysis: agreement and bias detection.
MAE by angular range: segmented mean absolute error.
RMSE by angular range: segmented root‑mean‑square error.

Associated file: SmartDroplet_Toolkit_BaseAlgorithms.tar

1. Tapias‑Boon System Validation

This component validates the image‑processing workflow integrated into the Tapias‑Boon System, a multi‑technique device for contact angle measurements under high‑pressure and high‑temperature (HPHT) conditions.

Validation datasets

1600 synthetic droplet contours generated using the SmartDroplet Toolkit (5°–173°).
Images of 3D‑printed reference geometries representing hydrophilic, mixed, and hydrophobic wetting scenarios.
Acquired images under realistic optical and geometric conditions.

The statistical evaluation confirms the robustness and accuracy of the integrated image‑processing algorithms.

Associated file: TapiasBoon_SystemValidation.tar

1. Contact Angle Measurement Tools

This section provides MATLAB tools and example datasets for three measurement techniques: sessile drop, captive bubble, and tilted plate.

3.1 Sessile Drop – Static contact angle determination using drops deposited on surfaces

This dataset contains MATLAB-based tools for measuring contact angles of liquid droplets on solid surfaces. It includes two main tools:

ContourFun – Detects and extracts droplet contours from images for geometric analysis.
CAFun_Sessile – Calculates contact angles based on the extracted droplet contour using established image analysis algorithms.

Example images are provided from an experiment conducted on a quartz substrate with a droplet of deionized water inside a pressurized chamber at 10 MPa and 110 °C using nitrogen.

Associated file: Sessile_Drop_(Base_Algorithms).tar

3.2 Captive Bubble – Measurement using bubbles trapped at liquid interfaces

This dataset contains MATLAB-based tools for measuring contact angles of gas bubbles on solid surfaces. It includes three main tools:

Rotate90Fun – Rotates the images 90° counter-clockwise to ensure a consistent analytical orientation along the X-axis, preventing the droplet profile from having multiple Y-values at a given X-coordinate.
ContourBubbleFun – Automatically processes droplet images to extract clean left and right contour profiles using ROI selection, filtering, binarization, and perimeter detection.
CABubbleFun – Computes left, right, and average contact angles from the extracted contour data using cross-product slope analysis, parabolic fitting, and statistical validation tools.

Example images for workflow demonstration are included.

Associated file: Captive_Bubble_(Base_Algorithms).tar

3.3 Tilted Plate – Dynamic angle measurement using automated inclined surfaces

This dataset provides MATLAB-based tools for measuring the contact angles of droplets on surfaces that are tilted under precise angular control. It includes four primary tools:

ContourFun – Extracts droplet contours from images and stores left and right side coordinates for further analysis.
SubstrateTiltFun – Determines the substrate baseline angle for each droplet and generates adjusted tilt values for image alignment.
rotateTiltFun – Rotates images according to the baseline tilt, producing a consistent orientation for accurate contact angle measurement.
CATiltFun – Calculates left and right contact angles using slope analysis and polynomial fitting, visualizes droplet data, and exports results as CSV.

Example images are provided from an experiment conducted on a quartz substrate with a droplet of deionized water inside a pressurized chamber at 10 MPa and 20 °C using nitrogen. The set includes more than 200 images covering an angular range from 0° to 90°, with an angular speed of 0.45°/frame.

Associated file: Tilted_Plate_(Base_Algorithms).tar

1. Documentation

Each MATLAB script (.m) includes a detailed README covering:

Purpose and general description.
Configurable parameters.
Step‑by‑step workflow.
Output formats and generated figures.
Required input files.

1. Applications

   Surface science and wettability research. Coating and material characterization. Algorithm development and benchmarking. Education in interfacial phenomena. HPHT experimental method development.

2. Purpose of the Dataset

This dataset accompanies and supports the findings of the associated research article. It enables reproducibility of experiments, independent validation of algorithms, transparent documentation of the Tapias‑Boon System, and open‑source dissemination of measurement tools.

1. Repository

The latest versions of scripts and updates are maintained in the GitHub repository:

https://github.com/FabianTapias