Tailoring the adhesion properties of thin polymeric films using additives: an AFM study

Area of Science:

• Materials Science
• Polymer Chemistry
• Surface Science

Background:

• UV-cured thin films are crucial for coatings and printing primers.
• Surface properties significantly influence film performance.
• Understanding additive effects is key for material optimization.

Purpose of the Study:

• To investigate how silicone-modified and silicone-free polyether additives affect UV-cured film adhesion.
• To determine the optimal additive concentration for enhanced adhesive properties.
• To elucidate the mechanisms behind surface modification and nanomechanical changes.

Main Methods:

• Incorporation of two distinct polyether additives into 12 µm UV-cured polymer films.
• Surface analysis to confirm additive segregation using atomic force microscopy (AFM).
• Measurement of adhesive work via force-distance curves to quantify adhesion changes.

Main Results:

• Both additive types segregated to the film surface, modifying surface properties without altering the bulk.
• Adhesive properties improved up to an optimal concentration of 10 wt%.
• Above 10 wt%, adhesion plateaued, with excess additives entering the bulk, indicating altered polymer ordering and nanomechanical response.

Conclusions:

• Polymeric surface modification with specific additives can significantly enhance adhesion in UV-cured films.
• An optimal additive concentration exists, beyond which bulk properties are affected, suggesting changes in molecular ordering or crosslinking.
• Findings are critical for applications like flexographic printing on metallic surfaces.