Covalently bonded layer-by-layer assembly of multifunctional thin films based on activated esters

Area of Science:

• Polymer Science
• Materials Science
• Nanotechnology

Background:

• Layer-by-layer (LbL) deposition is a versatile technique for fabricating multilayer films.
• Covalent bonding offers enhanced stability compared to non-covalent interactions in LbL films.
• Developing multifunctional and stable polymer thin films is crucial for advanced applications.

Purpose of the Study:

• To demonstrate a method for creating chemically stable, multifunctional polymer thin films using LbL deposition with covalent bonding.
• To investigate the effect of polymer solubility on reaction conversion during LbL assembly.
• To showcase the ability to incorporate multiple functional materials and create patterned surfaces.

Main Methods:

• Layer-by-layer (LbL) deposition of poly(pentafluorophenyl-4-vinylbenzoate) (P1) or poly(pentafluorophenylacrylate) (P2) with poly(allyl amine) (PAAm).
• Amide bond formation via reaction between activated esters and amine groups, monitored by Fourier transform infrared spectroscopy (FT-IR).
• Post-treatment functionalization with dyes (EDANS and Rhodamine B) and surface patterning.

Main Results:

• LbL multilayer films were successfully fabricated through covalent amide bond formation.
• Polymer solubility influenced reaction conversion, with P2 showing higher conversion than P1.
• Incorporation of multiple functional materials and surface patterning were achieved.
• The resulting films exhibited high stability across a wide pH range and could be obtained as free-standing structures.

Conclusions:

• Covalently bonded LbL films offer excellent chemical stability and multifunctionality.
• The LbL approach provides a versatile platform for designing flexible, thin film structures.
• These films hold significant potential for diverse chemical and biological applications.