Flow Cell Lab Activity

Introduction to Flow Cells

Typical Y-Flow Cell with Laminar Flow

The purpose of this experiment was to see if distinguishing a flow cells mixing area would change the flow through the system. In a regular T- or Y-flow cell there is a laminar flow, a flow in which the two sides do not mix, that can be manipulated to give a non-laminar flow through the system. Using ten different manipulation of a typical flow cell, a way of having a non-laminar flow was experimented. Blue and yellow dyed RO water was used to determine the laminar/non-laminar flow of the flow cells by way of peristaltic flow pumps and gravity filtration. These flow cells were created using TinkerCAD to make a virtual object, 3D printed, and cast with silicon. To attach the pumps, either peristaltic or gravity, to the flow cell, an acrylic plastic was drilled and tapped at the precise measurements of the individual flow cells created. Each flow cell was used and it was determined which resulted in laminar flow and which resulted in non-laminar flow as shown below.

Producing The Virtual Object

Getting Started with TinkerCAD

• Go to the TinkerCAD website (https://www.tinkercad.com/)
• Create an account or Login to an existing account
• Click on Create a New Design to get started.
• There are tutorials available in TinkerCAD to get used to object placements and using different shapes. Also refer this link (https://www.tinkercad.com/quests/)

Dimensions of the Mold

• The Outer Box : 56 mm X 26 mm with a height of 7 mm with a 2 mm bottom
• Interior Channels : Channel height is 2 mm and the width of each channel is 2 mm

Things to Note

• Use cylinders for mixing chambers instead of spheres to avoid undercuts.
• For channels, ideally use boxes instead of half cylinders or cylinders.

Exporting the file

Once the design is complete. Click the "Design" tab located to the top left corner of the screen and export the file as .STL

Box Dimensions

Exporting File

Prep for 3d Printing

A gcode file is required in order to print an object on the 3D printer. This file can be created by exporting one's Tinkercad object as an STL. The STL file can be imported into Matter Control.

The gcode file contains settings specific to the 3D printer being used in production of the flow cell. As a result, one must ensure that the proper printer, material, and settings are chosen before exportation of the final gcode.

Select The Printer in Matter Control	Matter Control Layer Settings	Matter Control Infill Settings	Matter Control Raft Settings
	Matter Control Support Settings	Matter Control Filament Settings	Matter Control Cooling Settings

Silicon Casting

After the 3D-printed cast has been made, now the actual flow cell can be created. We have used a 10:1 ratio of Slygard 184 (a silicon monomer) to curating agent, or about 5 grams Slygard 184 to 0.5 grams curating agent. After this is mixed thoroughly, we pour it into the cast and place it in a desiccator and place a vacuum on it to let the air bubbles come to the surface; once the vacuum is taken off, the bubbles will pop if left long enough.

Silicon mold in Desiccator

After this, we can leave the cast to curate, or let the silicon harden and shape to the cast. There were a few ways this was done. Some put their cast into the oven, but due to the low melting temperature of the acrylic plastic, they started to melt, making them unable to be reused. Others, however, left theirs out over the time span of a week to harden. A table of how they have been done is listed below.

Curing Times

Flow Cell Construction

After completing the casting, the mold was placed on two glass slides. This created a sandwich in which solution could pass through. Holes were drilled on one of the glass slide, corresponding to each model using a driller of size 2mm. Adapters between the slide holes and mold model were utilized to allow the solutions inside. Solutions were made using color dyes blue and yellow in 500 ml of water. A waste beaker was used to collect the mixed solutions. Peristaltic pumps were used to pump the colored solutions into the flow cell. The rate of pumping differed in every model.

Flow Cell Experimentation

Physical Chemistry 2 April 2016 Results
	Brad	Chris	Morgan	Tyler	Ian	Kayla	Matt	Priscilla	Deysi	Sujith
Model
Printed Mold
Result