Superhydrophobic surfaces formed using layer-by-layer self-assembly with aminated multiwall carbon nanotubes

Area of Science:

• Materials Science
• Nanotechnology
• Surface Chemistry

Background:

• Functionalization of multiwall carbon nanotubes (MWNTs) is crucial for tailored applications.
• Polyethyleneimine (PEI) offers amine groups for facile surface modification.
• Controlling surface properties like hydrophobicity is key for advanced materials.

Purpose of the Study:

• To develop a simple method for functionalizing MWNTs with PEI.
• To explore the assembly of these functionalized MWNTs into nanocomposite films.
• To create superhydrophobic surfaces on polyethylene using layer-by-layer assembly.

Main Methods:

• Reaction of MWNTs with PEI in N,N-dimethylformamide (DMF).
• Characterization using elemental analysis, thermogravimetric analysis, and titration.
• Layer-by-layer assembly (covalent and ionic) onto polyethylene substrates.
• Surface analysis via contact angle, AFM, and confocal Raman microscopy.

Main Results:

• Successfully synthesized MWNT-NH-PEI with 6-8% PEI content.
• MWNT-NH-PEI nanoparticles form stable aqueous emulsions below pH 9.
• Nanocomposite films exhibited superhydrophilicity with micro/nanoroughness.
• Superhydrophobic PE films achieved with contact angles up to 165° and low sliding angles.

Conclusions:

• A straightforward route to functionalized MWNTs (MWNT-NH-PEI) was established.
• These functionalized nanotubes enable the creation of superhydrophobic surfaces on polyethylene.
• Covalently assembled films demonstrate superior chemical robustness compared to ionically assembled films.