Category Archives: Nanolitre-Dosage-Applications

Piezoelectric

 

Dispensers

Dispensable Liquids

Will my Sample work with GeSiM Dispensers?

Many liquids which fit into the viscosity range can be used with piezoelectric GeSiM dispensers. Other important parameters are density and surface tension. The latter one is important for generating smooth drops when the liquid passes the orifice.


Please download the product brochure for a selection of dispensable liquids.

 

Dispensing of Adhesives

Application Example for heatable Dispensers

Adhesives often have high viscosities. There are two ways to dispense them: the design of the microdispenser can be optimized for higher viscosities or the viscosity is reduced by heating. GeSiM microdispensers should not be heated to more than 120 °C, i.e., the viscosity of the liquid should not exceed 5 mPa·s at 120 °C.

Droplet velocity (blue) and diameter (red) vs. excitation voltage at 90 °C for UVO-114

Droplet velocity (blue) and diameter (red) vs. excitation voltage at 90 °C for UVO-114

The UV-curable adhesives OG169 and UVO-114 (Epoxy Technologies) could be dispensed (viscosities at room temperature: 82 mPas and 300 – 700 mPas, resp.) The left image depicts the dependence of droplet velocity and diameter on the excitation voltage for UVO-114; the inset of Fig. 1 shows a picture of a single droplet of adhesive in front of the dispenser nozzle.

The right side picture shows an array of single epoxy spots on glass, made by the Nano-Plotter. The spot size is about 200 µm and can be varied using different piezo settings. Although the viscosity of OG169 is much lower than that of UVO-114, it needs a higher temperature for dispensing.

Array of UVO-114 with a spot diameter of ~ 200 µm on a glass slide

Array of UVO-114 with a spot diameter of ~ 200 µm on a glass slide

A number of liquids (e.g. glycerol) were successfully tested. Inthe case of two-component epoxies, the individual components must be dispensed using two different microdispensers. Mixing and curing of the epoxy then takes place on the substrate, one example being 301-2 from Epoxy Technologies.

 

Collision of Microdroplets

The Droplet Collider – Target, Hit, Merge…

Microdroplets ejected by the piezoelectric GeSiM dispensers fly at a speed of about 4 m/s. The high kinetic energy supports mixing of mixable liquids.

Piezoelectric Nanolitre Droplet Collider: Setup with temperature control unit and piezo driver (Left); Two heatable piezoelectric dispensers in front of a stroboscope unit (Right)

Piezoelectric Nanolitre Droplet Collider: Setup with temperature control unit and piezo driver (Left); Two heatable piezoelectric dispensers in front of a stroboscope camera (Right)

 

The GeSiM Droplet Collider is based on a manual swivel to host two piezoelectric microdispensers. Micrometer calipers allow to adjust position and angle of nozzles to make sure simultaneous ejected drops hit on air.

 

  • Stroboscope video of mixing process

    Stroboscope video of mixing process

    Stroboscope camera for visual alignment and drop inspection

  • Cartridge based sample delivery
  • Individual settings for both dispensers