Open-Loop, Barrier-Free, Continuous Langmuir-Blodgett-Based Multipass Multilayer Deposition.

Area of Science:

• Materials Science
• Surface Chemistry
• Nanotechnology

Background:

• Traditional Langmuir-Blodgett (LB) assembly is limited in scalability for thick multilayers due to slow, discrete deposition cycles.
• Achieving controlled, large-scale particulate multilayer fabrication remains a significant challenge in materials science.

Purpose of the Study:

• To develop a novel, scalable, and continuous-feed LB-based platform for fabricating particulate multilayers.
• To investigate the relationship between operational parameters and multilayer film formation in a recirculating system.

Main Methods:

• A barrier-free, open-loop platform recirculating a flexible polyethylene terephthalate (PET) substrate through an air-water interface was designed.
• Surface pressure was monitored in situ using a Wilhelmy plate to track interfacial evolution.
• Experiments varied substrate speed (v) and injection rate (Q) using a methanol-based SiO2 dispersion to study deposition dynamics.

Main Results:

• The continuous-feed system successfully built robust, micrometer-scale porous multilayers in a single, uninterrupted run.
• Deposition initiated as localized streaks and patches, influenced by meniscus interactions during substrate recirculation.
• Film loading was found to be dependent on controlled operating conditions like substrate speed and injection rate.

Conclusions:

• A parameter-based framework was established, linking substrate speed and injection rate to interfacial evolution and multilayer buildup.
• The developed platform offers a scalable interfacial deposition strategy with retained LB-like process visibility.
• This approach overcomes limitations of conventional LB assembly for producing thick, particulate multilayers.