Microfluidic Preparation of Liquid Crystalline Elastomer Actuators.

Area of Science:

• Materials Science
• Soft Matter Physics
• Microfluidics

Background:

• Liquid crystalline elastomers (LCEs) are stimuli-responsive materials with tunable properties.
• Actuating particles derived from LCEs offer potential for micro-robotics and smart devices.
• Precise control over particle morphology and actuation is crucial for their application.

Purpose of the Study:

• To investigate the microfluidic process for preparing actuating particles from LCEs.
• To explore the influence of process parameters on particle characteristics and actuation.
• To demonstrate the fabrication of complex LCE particle architectures.

Main Methods:

• Droplet formation of low molar mass liquid crystals in a microfluidic capillary.
• Flow field-induced orientation of liquid crystal precursors.
• Solidification via crosslinking polymerization to form LCE actuating particles.
• Systematic variation of microfluidic parameters (temperature, flow rate).

Main Results:

• Microfluidic parameters precisely control particle size and shape, ranging from oblate to prolate morphologies.
• Actuation magnitude and type (elongation/contraction) are tunable by adjusting the director profile during flow.
• Complex particle designs, including core-shell and Janus structures, are achievable.
• LCE particles can be triggered by heat or UV-vis irradiation by altering chemical structure and crosslinking.

Conclusions:

• Microfluidics provides a versatile platform for fabricating LCE actuating particles with controlled properties.
• The process allows for fine-tuning of particle morphology, actuation behavior, and responsiveness.
• This method enables the development of advanced smart materials for diverse applications.