Solvent-Mediated Diffusion Enables Directed Functionalization of Polymer Semiconductor Interfaces

Area of Science:

• Materials Science
• Polymer Chemistry
• Surface Science

Background:

• Stretchable electronic devices require understanding polymer semiconductor film interfaces.
• Solvent-mediated functionalization offers a scalable method to tune interfacial properties.
• Controlling interfacial properties is crucial for layer compatibility in electronic devices.

Purpose of the Study:

• To investigate the influence of solvent exposure on the functionalization of blended polymer films.
• To understand how different solvent environments affect small molecule incorporation.
• To explore the programming of functionalization gradients within polymer semiconductor films.

Main Methods:

• Utilized a blended film of poly-thieno[3,2-b]thiophene-diketopyrrolopyrrole (DPPTT) and polybutadiene (BA).
• Incorporated 1H,1H,2H,2H-perfluorodecanethiol (PFDT) via solvent-mediated functionalization.
• Employed Quartz Crystal Microbalance with Dissipation monitoring (QCM-D) and X-ray Photoelectron Spectroscopy (XPS) depth profiling.

Main Results:

• Demonstrated solvent-controlled PFDT incorporation, yielding uniform or gradient functionalization.
• Non-swelling solvents resulted in diffusion-governed PFDT uptake with thickness-dependent gradients.
• Swelling solvents (methoxyperfluorobutane, MPFB) promoted uniform PFDT penetration throughout the film.

Conclusions:

• Established a method for programming functionalization gradients in polymer semiconductor films.
• Provided insights into molecular diffusion mechanisms within polymer semiconductor systems.
• Advanced the understanding of solvent-mediated interfacial engineering for stretchable electronics.