Projects
A home for my tinkering
Paper Microfluidics
Goals and Focus
The goal of this project was to replicate and improve upon the process for making paper microfluidics put forth in this paper by whitesides.
Outputs
Process Instructable
The Process that we found effective is outlined here on instructables.
Modifications and Integration into Other Projects
Progress Log
Attempts to power the circuit wirelessly was unsuccessful but allot was learned in antenna design along the way.
After getting functioning channel we moved to try and integrate the microfluidic with some electronics, the microfluidic was placed in a lickometer circuit so that ounce the fluid traveled through the channel electrical contact was made with a transistor allowing an LED to light.
Success! Finally able to get a functioning channel, we determined that the was penetration through the paper was limited when heating (We have switched to a laminator instead of stove top heating) to combat this we printed on both sides of the paper effectively Halfling the distance it needed to travel.
When in doubt design of experiments! This is my motto when in the beginning of a project, turning the frustration of failure into a more systematic form of elimination, also helpful to determine whether you are focusing on the wrong thing. We focused on channel thickness and wall thickness.
After obtaining the printer, we went off Whitesides’ instructions(https://gmwgroup.harvard.edu/pubs/pdf/1060.pdf) reproducing a similar pattern to that in figure 3. D and E in the paper. The results as seen below were not very successful. Even after trying different “baking times” (in seconds written on the individual patterns) on a 150C kitchen pan, all seemed to have the water leak outside the boundaries. Looking back the main two issues that I believed caused this was too large of a reservoir with walls not thick enough and the wax not penetrating fully through the paper.
The first attempt was with Crayon wax on chromatography paper, baking it on a pan in the kitchen. This failed and resulted in the whole paper becoming hydrophobic, it is believed that the was spread over the whole paper, not taking all the pigment with it.
