Electrogelation: Controlled Fast Formation of Micrometer-Thick Films from Low-Molecular Weight Hydrogelators

Area of Science:

• Materials Science
• Electrochemistry
• Supramolecular Chemistry

Background:

• Controlled formation of thin hydrogel films is crucial for advanced applications.
• Low-molecular weight hydrogelators (LMWHGs) offer versatile building blocks for hydrogel synthesis.
• Electrochemical methods provide precise control over material deposition.

Purpose of the Study:

• To investigate the controlled electrochemical deposition of hydrogels from LMWHGs.
• To study the formation of supramolecular fibrillar networks of N,N',N″-tris(4-carboxyphenylene)-1,3,5-benzenetricarboxamide (BTA) on gold electrodes.
• To understand the influence of deposition parameters on film characteristics.

Main Methods:

• Electrochemical deposition (electrogelation) of BTA sodium salt on ultraflat gold electrodes.
• Utilizing electrolysis of water to induce local pH changes for hydrogel self-assembly.
• Characterization of hydrogel film thickness using atomic force microscopy (AFM), including ex situ and in situ techniques.

Main Results:

• Achieved highly accurate control over hydrogel film thickness (within tenths of nanometers).
• Demonstrated rapid film formation (seconds) at moderate applied potentials.
• Identified key parameters influencing deposition: gelator concentration, applied potential, and gelation time.

Conclusions:

• Electrogelation is a viable method for controlled deposition of pH-responsive hydrogel films.
• The findings are transferable to other pH-responsive LMWHGs and reversibly formed hydrogel films.
• The rapid and precise nature of electrogelation makes it suitable for biomedical applications.