Contact angle analysis on polymethylmethacrylate and commercial wax by using an environmental scanning electron...

Area of Science:

• Materials Science
• Surface Science
• Microscopy

Background:

• Environmental scanning electron microscopy (ESEM) enables observation of uncoated and hydrated samples.
• ESEM allows investigating surface wettability by creating micron-scale water drops.
• A key challenge in ESEM is measuring contact angles due to non-ideal observation angles, preventing standard analysis methods like axisymmetric drop shape analysis (ADSA).

Purpose of the Study:

• To develop a mathematical model for accurately calculating real contact angles from ESEM images.
• To address the limitations of existing algorithms when applied to ESEM droplet profiles.
• To validate the model using simulated and real ESEM data.

Main Methods:

• Creation of simulated spherical caps with varying contact and observation angles.
• Acquisition of real water droplet images on wax and polymethylmethacrylate (PMMA) using ESEM.
• Application of a novel mathematical model to calculate contact angles from ESEM images.

Main Results:

• The developed mathematical model successfully calculates real contact angles from ESEM images.
• Simulated data confirmed the model's accuracy across different observation angles.
• Results from real ESEM experiments on wax and PMMA showed good agreement with conventional contact angle measurement methods.

Conclusions:

• The proposed mathematical model provides a reliable method for determining contact angles in ESEM.
• This advancement overcomes a significant hurdle in utilizing ESEM for surface wettability studies.
• The model enhances the utility of ESEM for materials science research involving hydrated surfaces.