Selective optical trapping and deposition of polymer and aromatic molecules from binary mixed solution

Area of Science:

• Optics and Photonics
• Materials Science
• Supramolecular Chemistry

Background:

• Precise manipulation of molecules is crucial for advanced materials and nanotechnology.
• Optical trapping offers a non-contact method for manipulating microscopic entities.
• Controlling the composition of molecular assemblies from mixed solutions remains a challenge.

Purpose of the Study:

• To demonstrate size-selective optical trapping and deposition of polymer and aromatic molecules.
• To investigate the influence of laser power on the composition of deposited molecular assemblies.
• To elucidate the mechanism of size selectivity in optical trapping for binary mixtures.

Main Methods:

• Utilizing a tightly focused near-infrared laser beam.
• Employing optical trapping to manipulate molecules in a polystyrene and perylene mixed solution.
• Depositing molecular assemblies onto a glass substrate at the laser focus.
• Analyzing the fluorescence spectra of deposited microassemblies at varying laser powers.

Main Results:

• Successful size-selective optical trapping and deposition of polymer (polystyrene) and aromatic (perylene) molecules.
• Laser power influences the molecular composition of the deposited assembly.
• High laser power favors polystyrene deposition, while low power results in perylene crystal excimer emission.
• Fluorescence spectra indicate preferential deposition based on laser power, suggesting molecular size selectivity.

Conclusions:

• Size-selective optical trapping enables controlled deposition of different molecules from binary mixtures.
• Laser power is a critical parameter for tuning the molecular ratio in optical deposition.
• The findings provide a mechanism for creating tailored molecular assemblies using optical forces.