Model fluorous polyurethane surface modifiers having co-polyoxetane soft blocks with trifluoroethoxymethyl and...

Area of Science:

• Polymer Science
• Surface Chemistry
• Materials Science

Background:

• Conventional polyurethanes often require surface property modification for specific applications.
• Introducing fluorinated segments can alter surface energy and wetting behavior.
• Understanding the influence of block copolymer composition on surface modification is crucial.

Purpose of the Study:

• To investigate the surface modification capabilities of fluorous co-polyoxetane soft blocks in conventional polyurethanes.
• To evaluate the effect of varying fluorous content (3FOx:BrOx ratios) on surface properties and wetting behavior.
• To determine the role of brominated segments in surface concentration and modification.

Main Methods:

• Synthesis of polyurethanes with poly(2-trifluoroethoxymethyl-2-methyl)-co-(2-bromomethyl-2-methyl)-1,3-propylene oxide) soft blocks.
• Surface modification of a base polyurethane [isophorone diisocyanate/butanediol hard block and polytetramethylene oxide soft block] with fluorous co-polyoxetane (0.5-2 wt %).
• Characterization using tapping mode atomic force microscopy (TM-AFM), X-ray photoelectron spectroscopy (XPS), and dynamic contact angle (DCA).

Main Results:

• Fluorous polyurethane surface modifiers (0.5-1.0 wt %) yielded surface properties similar to the parent material.
• Increased ratios of 3FOx:BrOx enhanced water wetting behavior retention, indicating increased fluorous character.
• Poly(bromomethyl-2-methyl)-1,3-propylene oxide) soft blocks showed negligible bromine at the surface and did not act as effective surface modifiers due to miscibility with the bulk polyurethane.

Conclusions:

• Fluorous co-polyoxetane blocks can modify polyurethane surfaces, enhancing wetting behavior retention with higher fluorous content.
• The lack of surface concentration for brominated polyoxetane blocks is attributed to their miscibility with the base polyurethane and lack of specific end-group architecture.
• Effective surface modification requires careful consideration of block copolymer composition and architecture to control surface energy and functional group presentation.