Spin-Coating Has My Head Spinning

The Infamous Spin Coater

The Infamous Spin Coater

Working in research lab is a lot like a rollercoaster; there are ups and downs, sometimes it moves fast, other times it’s painfully slow, and sometimes it seems to be spinning you in circles. One of our instruments actually does spin things around in circles: the spin coater. The spin coater vacuum seals a glass slide to its rotating arm, and spins it at high velocity┬áto evenly coat our sample on the slide. But how evenly is it really coating the slides? Through my research I’d venture to say it’s temperamental. Some days it only takes me two tries to a molecule-filled area, whereas other days I’ll try for 30 minutes before finding a single molecule beyond reasonable doubt. The following images are excellent examples of what I’m talking about:


10^-9 M Alizarin/EtOH Too many molecules to count

10^-9 M Alizarin/EtOH
Too many molecules to count

10^-9 M Alizarin/ EtOH Approx. 5 molecules

10^-9 M Alizarin/ EtOH
Approx. 5 molecules








So what’s happening? Well let’s redefine our perspective, we’re trying to find single, individual molecules. That is not a necessarily simple task, and the spin coater is not supposed to make our search perfect, it is supposed to make it easier. Our spin coater is doing the best it can under the circumstances, so I guess I should cut it some slack. At the end of the day, spin-coating is going spread unevenly on the slide as long as there is any amount of viscosity to our sample. In the future I can try sonicating my mixtures for longer periods of time to break up any aggregates that have formed.


  1. crtravis says:

    Hi Kaelyn!

    Your research sounds like it can be time-consuming and tedious, but seems to be rewarding as well.

    I definitely understand what you mean with things working some times and not others, even though it seems to us as researchers that we are doing the same thing — the same thing has happened to me too often this summer. Equipment may not always cooperate, but I suppose part of our job is to work through the shortcomings of equipment to move forward with our projects.

    Best of luck in finishing up your project!