Two-Dimensional Mechanics of Atomically Thin Solids on Water.

Area of Science:

• Materials Science
• Nanotechnology
• Fluid Dynamics

Background:

• Solid movement at air-water interfaces is significantly affected by external factors like capillary interactions and water drag.
• Existing methods struggle to isolate intrinsic material properties due to these extrinsic influences.

Purpose of the Study:

• To develop a method for fabricating and imaging freely floating two-dimensional (2D) materials on water.
• To minimize extrinsic interactions and study intrinsic dynamics and mechanics of atomically thin solids.
• To demonstrate controlled manipulation of these 2D solids using external stimuli.

Main Methods:

• Synthesized wafer-scale monolayer molybdenum disulfide (MoS2) was delaminated onto a water surface.
• Laser patterning was employed to create arbitrarily shaped MoS2 structures with minimal in-plane strain.
• Photoswitchable surfactants were utilized to apply controlled lateral forces to the floating MoS2.

Main Results:

• Freely floating MoS2 solids were successfully fabricated with negligible height difference across the water and material.
• Arbitrarily shaped MoS2 structures were patterned with high fidelity and minimal strain.
• Spatiotemporal control over the lateral movement of MoS2 solids was achieved using photoswitchable surfactants.
• Demonstrated reversible shape changes in various 2D mechanical systems.

Conclusions:

• This work presents a versatile platform for studying intrinsically 2D dynamics and mechanics of atomically thin solids.
• The developed method allows for precise design and control of 2D materials floating on water.
• Opens new avenues for creating and manipulating novel 2D mechanical systems.