Reconfigurable colloid-crystal materials for fine control over particle motion

A nematic liquid crystal system functionalized with colloidal microbots.

Problem:

Particle motion is of great interest for designing materials that depend on the particle behavior to exhibit a specific functionality. Elastic colloids are useful for the development of functional materials for particle manipulation. Nematic liquid crystals are fluid, like liquids, but also have well-defined structural organization, like crystals.

Embedding colloids in these materials provides strong control over the particle motion and ensures a smooth elastic energy field for the particles. Current techniques have similarly tried to alter the energy landscape for particles in colloid-nematic crystal systems, but fail to robustly control the particles, and either do not solicit a response or drastically change the crystal configuration.

Solution:

The researchers envision controllable, reconfigurable liquid/crystal systems. To achieve this innovation the inventors leverage surface features in boundary walls that cause unique boundary conditions that can control the movement and action of microbots within the system. These colloidal systems and microbots can be fabricated for specific application requirements.

Figures: (a)Elastic energy field and the resulting forces for colloids near the wall in a Saturn ring configuration (c) Schematic of the experimental setup (N denotes rubbing direction) (f + g) A magnetic particle with a Saturn ring defect, placed near a hill, with wall to wall separation (yellow) 60 μm and (blue) 42 μm

Applications:

• Materials/surfaces that self-repair or self-heal
• Targeted delivery tools, such as drug delivery
• Manufacturing on a micro-scale
• Cargo-delivery in micro-robots

Advantages:

• Improved control over particles
• No drastic change in configuration of crystals
• Defects can be used to drive particle motion for colloidal assembly

Stage of Development:

• Ongoing experimental work with cargo-carrying prototypes
• Prototypes will be used for proof-of-concept experiments that test control of unstable points and path planning of particles
• Colloidal assembly at the defect sites will be demonstrated

Intellectual Property:

Patent Pending

Reference Media:

Luo, Y et al; Nat Commun 2018 Sept 21, 9(1): 3841. 

Docket # 18-8616