- Tamir, Uyanga [Browse]
- Senior thesis
- 47 pages
- Priestley, Rodney D. [Browse]
- Princeton University. Department of Chemical and Biological Engineering [Browse]
- Class year
- Summary note
- Anisotropically structured, compartmentalized colloids have sparked great interest
in recent research due to their ability to exhibit multiple functionalities. One such
superstructure that self-assembles is polymer Janus particles with biphasic geometry.
Many methods have been developed to fabricate Janus particles yet its complete
characterization and scalability have remained a challenge. The formation of Janus
particles using the Dialysis NanoPrecipitation method remains unexplored and can
provide valuable information about these challenges.
In this study, the effects of overall polymer concentration, relative homopolymer
ratio, and polymer molecular weight were studied on polystyrene/polyisoprene Janus
particles fabricated by the Dialysis NanoPrecipitation method. Additionally, timed
experiments were conducted with increasing duration of dialysis in order to understand
the assembly mechanism of Janus particles.
It was found that Janus particle molecular weight and size can be independently
tuned by varying the overall concentration of the polymer feed. Furthermore, the surface
domain composition of Janus particles made by Dialysis NanoPrecipitation can be tuned
by altering the ratio of homopolymers that constitute the two domains. Particles made
using high molecular weight polymers (> 1,000 kg/mol) exhibited multi-faced structures,
departing from the Janus morphology. Lastly, the results of the work suggest that particle
growth is characterized by two regimes, one marked by rapid nucleation and phase
separation followed by a second regime of fusion and growth.