Method and system for Langmuir-Blodgett assembly
This invention relates to method and system for forming a film. The method including providing a trough containing water defining an air-water interface between air and the water; providing a solution containing a material of interest; and electrospraying the solution onto the air-water interface of water to form a film of the material of interest at the air-water interface. The system includes a trough containing water defining an air-water interface between air and the water; and means for spreading a solution containing a material of interest onto the air-water interface of water by electrospray, to form a film of the material of interest at the air-water interface. The spreading means comprises an electrospraying device.
1. A system for forming a film, comprising:
a trough containing water defining an air-water interface between air and the water, and having at least two barriers being separated from and movable in parallel to each other to define an area therebetween on the air-water interface;
an electrospraying device comprising a syringe having a metal needle connected to a power supply set at 10 kV and positioned above the air-water interface, configured to spread a solution containing a material of interest onto the air-water interface of water at a feed rate in a range of 0.5-2.0 ml/h, without producing air flow to disturb the air-water interface, to form a film of the material of interest in the area between the at least two barriers at the air-water interface; and
a grounding wire submerged in a water subphase from a place outside the area between the at least two barriers in the trough,
wherein the area between the at least two barriers is changeable by parallel moving the at least two barriers on the air-water interface so as to tune a particle packing density of the film formed in the area; and
wherein the trough is equipped with a tensiometer and a dip coater for recording an isothermal surface pressure-area curve of the film formed in the area.
2. The system of claim 1 , wherein the syringe is connected to a syringe pump to control a flow rate of the solution.
3. The system of claim 1 , wherein the solution contains a dispersion of the material of interest in water, a water-miscible solvent, or a mixture of them.
4. The system of claim 1 , wherein the solution contains a stock solution of the material of interest.
5. The system of claim 4 , wherein the stock solution contains a water-miscible solvent.
6. The system of claim 5 , wherein the stock solution of the material of interest is devoid of a surface medication or a solvent exchange.
7. The system of claim 4 , wherein the solution further contains a water-miscible solvent added into the stock solution of the material of interest in water.
8. The system of claim 1 , wherein the solution contains aqueous colloidal dispersions.
9. The system of claim 1 , wherein the material of interest comprises Au/polyvinylpyrrolidone (PVP) particles, polystyrene (PS) beads, polyaniline (PANI) nanofibers, graphene oxide (GO) sheets, nanoparticles of other materials, or biological colloids.
10. The system of claim 1 , wherein the film is of a monolayer.