Versatile strategy for achieving uniform molecular deposition in evaporation drops

Area of Science:

• Materials Science
• Surface Engineering
• Biomedical Engineering

Background:

• Uniform evaporative deposition is critical for diverse applications like electronic tattoos and inkjet printing.
• The coffee-ring effect, caused by preferential material accumulation at the contact line, hinders uniform molecular deposition.

Purpose of the Study:

• To develop a versatile strategy for achieving uniform molecular deposition.
• To investigate the role of cellulose nanofibers (CNFs) in suppressing the coffee-ring effect.

Main Methods:

• Utilized cellulose nanofibers (CNFs) for deposition experiments.
• Conducted theoretical analysis to understand the mechanisms involved.
• Tested the strategy across various substrates including glass, leaves, and skin.

Main Results:

• CNF percolation induced steric hindrance and viscosity modulation, suppressing outward capillary flow.
• Strong molecular adsorption onto CNF surfaces ensured uniform deposition.
• Demonstrated successful applications in photodynamic antibacterial sprays and bacterial counting.

Conclusions:

• CNFs offer a robust platform for uniform molecular deposition, overcoming coffee-ring effects.
• The strategy is applicable to a wide range of materials and substrates.
• Opens new avenues for advancements in biomedicine, electronics, agriculture, and materials science.