A Method to Produce Janus Particles in Large Quantity

This innovation provides a simple and generalizeable method to synthesize Janus colloidal particles in large quantity. Janus particles offer unique opportunities in particle engineering for building particular structures; offering insight into the movement of particles and serving as a basis for new materials and sensors. Earlier methods to produce Janus particles of colloidal size (=1m in dimension) have been severely limited in the amount of product, but this method has overcome limitations on yield.

At the liquid-liquid interface of emulsified molten wax and water, untreated particles adsorb and are frozen in place when the wax solidifies. The exposed surfaces of the immobilized particles are modified chemically.

The wax is then dissolved and the inner surfaces are modified chemically. Janus particles, which have different chemical properties at different locations, could be used as potential building blocks for new 3D self-assembled structures. However, this purpose in particular requires a method to produce large quantities of material.

This invention offers tremendous control over the Janus Balance, the ratio of the two treated areas on each particle. The invention includes a number of ways to control this Janus Balance, giving the developer one more parameter to use in optimizing the end product.


  • Drug delivery: within the context of functional, biologically active molecules with polar moieties
  • Coatings: improved stability, color development, and viscosity control by choosing the right particle treatments and "Janus Balance" of the treatments
  • Nanoencapsulation: a wider range of functions in which the behavior of the particles can be determined by the surface composition
  • Stabilization of emulsions and foams
  • Cosmetic formulations


  • High yield: The process is solution-based with an approximate 50% yield, allowing hundreds of grams of particles to be made per batch. This is several orders of magnitude larger than with traditional methods 
  • Manufacturability: The process uses mature, readily available technologies to synthesize the particles 
  • Low cost: Mechanical mixing and large quantities make the process inexpensive 

Versatility: The process and particles can be applied to a wide variety of applications

To learn more about an application for this method, click here