Mdaughtrey writes in with a request for help modding an ink printer to print out circuits… –
So I’ve been tinkering with this, just using the chemicals and Q-tips to put it on paper. The conductivity is horrendously low so far (~300K ohms/cm) but I haven’t adjusted the pH of the solutions. My question is how do I do that? Ascorbic acid is, um…acidic, and I need to adjust to pH 7.2 and the silver nitrate to 6.5. Any ideas, anyone?
MAKE: Blog: Modified ink printer churns out electronic circuits – Link.
18 thoughts on “Modified ink printer churns out electronic circuits (experimenter needs help!)”
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I would add nitric acid. That way you’re not adding any new species to the solution.
Along the same vein, you can use sodium ascorbate instead of ascorbic acid.
Alternatively, you could try trisodium citrate. It is one of the most common reductants used in the literature (for Ag nanoparticle preparation), and as a base it might also fix the pH problem.
I’m really interested in staying true to the researchers’ original intent of environmental friendliness. If someone can reassure me that these are not toxic or can be neutralized prior to disposal, I’ll try them out.
Thanks for posting this up Phillip.
I’m doing some research right now that involves ascorbic acid that starts off at a pH of about 2.9, and I need it to be about 4.5… I just add a few drops of 1M KOH… that pretty much does the trick.
e chemicals listed thus far are environmentally friendly. in fact, *most* acids and bases are safe to dispose of down the drain, especialliy simple acids and bases involving sodium or potassium. Where you get into disposal problems is the heavy metals, such as chromium, cobalt, nickle, zinc, etc. which limits your from using things like chromic acid.
now, it’s still possible to be environmentally friendly using heavy metals, just DON”T DUMP THEM DOWN THE SINK!! there will be companies in your area that handle waste disposal of this nature, and although it might be expensive, they usually recycle all/most of the harmful stuff. the labs at the college pay a couple of hundred bucks each month for hazardous waste disposal of about 50 galons of mixed chemicals.
Ok, thanks for the feedback. One word of warning though; my prior chemistry experience consists of ripping off sodium and lithium from my high school and throwing it in a bucket of water (good times….), so “1M KOH” just make s my brain hurt. Talk down to me guys.
In the meantime I started playing with other variables and got it down to about 5ohms/cm last night. NOW WE’RE COOKING!
I do notice that my silver nitrate solution seems to “curdle” and get more viscous in the test tube after a few minutes which is going to make it hard to use in an inkjet printer. Contamination?
In Qual (where they give you a solution and say what is this?) the test for chloride, bromide and iodide is to add a drop of silver nitrate. If you see a big fluffy percipitate form then you got one of ’em.
Sounds to be like you got one of ’em. I’m going to bet chloride. If you’re not working with distilled water, I’d start. Also, when you wash your stuff, give it a final rinse in a bit of distilled water.
1M is a measure of concentration. It means one mole per liter. You know how they sometimes have masses on the periodic table? Well, one mole is the amount of stuff (number of atoms or molecules) it takes for you to have that mass in grams. So if you wanted to make a 1M solution of salt you’d put about 55 g of sodium chloride (the weight of sodium plus the weight of chlorine) in a liter of water.
Brilliant, thanks Austringer. Just before I left for work this morning I (conductive) glued an LED and a battery to one of the strips I made yesterday. The little sucker lit up!
I’m going to lay down a full matrix of combinations over the weekend to find out the optimal process. If I get my act together I’ll kick off a blog too.
Just wondering how far you took this? Any recent developments?