Spatio-temporal programming of lyotropic phase transition in nanoporous microfluidic confinements

Area of Science:

• Materials Science
• Chemical Engineering
• Biophysics

Background:

• Microfluidic devices offer controlled environments for studying molecular self-assembly.
• Nanoporous polydimethylsiloxane (PDMS) surfaces exhibit unique water uptake properties.
• Phase transitions in confined systems are influenced by surface properties and geometry.

Purpose of the Study:

• To investigate molecular assembly driven by nanoporous substrates in microfluidic channels.
• To explore the role of surface wettability, channel geometry, and topography in tuning phase transitions.
• To demonstrate programmable control over material assembly and particle manipulation.

Main Methods:

• Utilized a lyotropic chromonic liquid crystal as a model biological material.
• Employed timelapse polarized imaging and quantitative image processing.
• Developed a mathematical model to analyze phase transitions and construct a master diagram.

Main Results:

• PDMS nanoporosity, confinement, and wettability regulate the rate of the nematic-to-metamictic (N-M) phase transition.
• Microfluidic geometry and topography enable targeted phase transitions.
• Demonstrated elasto-advective transport for micro-cargo manipulation via tunable phase transitions.

Conclusions:

• Presented a programmable physical route for material assembly in microfluidic environments.
• Highlighted the potential for assembling genetic components, biological cargo, and synthetic cells.
• Established a new paradigm for controlling molecular self-assembly through engineered confinement.