Mechanism of surface molecular imprinting in polyelectrolyte multilayers

Area of Science:

• Polymer Science
• Materials Science
• Analytical Chemistry

Background:

• Layer-by-Layer (LbL) self-assembly enables controlled fabrication of polyelectrolyte multilayers (PEM).
• Molecular imprinting in polymers creates specific binding sites for target molecules.
• Combining LbL and molecular imprinting offers potential for enhanced molecular recognition and transport.

Purpose of the Study:

• To investigate the construction of LbL-assembled PEM incorporating template molecules.
• To analyze the binding and release dynamics of guest molecules within imprinted sites.
• To elucidate the role of pH in controlling template uptake and release mechanisms.

Main Methods:

• Utilized Layer-by-Layer (LbL) self-assembly for PEM fabrication.
• Employed Quartz Crystal Microbalance with Dissipation monitoring (QCM-D) to track film growth and molecular interactions.
• Manipulated solution pH to control template binding and release.

Main Results:

• Observed pH-dependent template removal and rebinding, correlating with film swelling.
• Interpreted QCM-D data to distinguish swelling effects from selective template binding kinetics.
• Provided evidence for selective binding into imprinted sites, leading to enhanced cross-linking (reduced dissipation).

Conclusions:

• The study demonstrates reversible template uptake and release in LbL-imprinted PEM.
• Film charge equilibrium, modulated by pH, governs the binding and release mechanism.
• LbL assembly combined with molecular imprinting provides a promising platform for controlled molecular recognition.