The Interaction Forces between Silica and Plasma-Treated Polypropylene Surfaces in Aqueous Solutions

Area of Science:

• Surface science
• Materials science
• Colloid and interface science

Background:

• Understanding surface interactions is crucial for material applications.
• Plasma treatment modifies polymer surface properties.
• Polypropylene and silica interactions are relevant in various industrial processes.

Purpose of the Study:

• To measure and analyze interaction forces between silica and plasma-treated polypropylene.
• To investigate the influence of plasma treatment on surface forces at different separation distances.
• To elucidate the mechanisms behind short-range repulsive forces.

Main Methods:

• Scanning Force Microscopy (SFM) was employed to measure interaction forces.
• Experiments were conducted in aqueous sodium chloride (NaCl) solutions.
• Data analysis involved fitting to the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory.

Main Results:

• DLVO theory accurately described forces at large and moderate distances.
• An additional repulsive force (<5 nm) was observed for plasma-treated polypropylene, absent in untreated samples.
• Higher surface potential and charge were determined for treated surfaces, attributed to C-OH groups and bicarbonate adsorption.

Conclusions:

• Plasma treatment introduces significant changes to polypropylene surface interactions.
• Solvation effects and bicarbonate ion adsorption are key factors in the observed short-range repulsion and surface charge.
• These findings are important for controlling interfacial phenomena in material science applications.