Shape-driven solid-solid transitions in colloids.

Area of Science:

• Materials Science
• Soft Matter Physics
• Thermodynamics

Background:

• Solid-solid phase transitions are fundamental in nature and technology, but their study is challenging due to extreme conditions and equipment limitations.
• Key questions persist regarding the thermal activation requirements of diffusionless solid-solid transitions, which involve local particle rearrangement.

Purpose of the Study:

• To investigate minimal model systems exhibiting solid-solid phase transitions driven by colloidal particle shape changes.
• To explore the thermodynamics of isochoric, diffusionless solid-solid transitions controlled by particle shape, differentiating between thermally activated and continuous processes.

Main Methods:

• Development of minimal model systems with colloidal particles whose shape can be altered.
• Thermodynamic investigation of diffusionless solid-solid phase transitions within a single particle shape family.
• Analysis of transition behavior concerning thermal activation and timescales.

Main Results:

• Identified solid-solid phase transitions that require thermal activation (discontinuous) and those that do not (continuous).
• Demonstrated that significant shape changes can drive discontinuous transitions on self-assembly timescales without an intermediate fluid phase.
• Observed continuous transitions occurring faster than self-assembly.

Conclusions:

• Particle shape is a viable control variable for inducing and studying solid-solid phase transitions, offering an alternative to traditional methods.
• The findings provide insights into the nature of diffusionless transitions, distinguishing between thermally activated and continuous pathways.
• This research offers guidance for the design and development of reconfigurable colloidal materials with tunable transition dynamics.