Wettability of PEDOT:PSS films

Area of Science:

• Materials Science
• Polymer Science
• Biomedical Engineering

Background:

• Conducting polymers, specifically poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), are vital for bridging electronics and biological systems.
• The wettability of PEDOT:PSS is poorly understood, hindering its optimal application in bioelectronic interfaces.
• Hydrogel-like behavior of PEDOT:PSS complicates standard wettability measurements.

Purpose of the Study:

• To investigate and clarify the wettability of PEDOT:PSS films.
• To compare the reliability of sessile drop and captive bubble techniques for measuring PEDOT:PSS wettability.
• To understand the impact of aging and crosslinking on PEDOT:PSS film hydrophobicity.

Main Methods:

• Utilized the sessile drop technique, noting its sensitivity to experimental conditions (duration, humidity).
• Employed the captive bubble technique on fully hydrated films to overcome limitations of the sessile drop method.
• Performed dynamic wettability measurements to determine hysteresis and static contact angles.

Main Results:

• Sessile drop technique results for PEDOT:PSS wettability are highly dependent on measurement duration and relative humidity.
• The captive bubble technique provides more reliable and consistent wettability data for PEDOT:PSS.
• Aging PEDOT:PSS films in water increases hydrophobicity due to PSS chain loss; crosslinking mitigates this effect.

Conclusions:

• The captive bubble technique is superior for accurate wettability assessment of PEDOT:PSS films.
• Understanding and controlling PEDOT:PSS wettability is essential for stable bioelectronic device performance.
• Crosslinking offers a viable strategy to enhance the stability and hydrophobic properties of PEDOT:PSS films over time.