All posts by Mr.G

Finally done with the AFM scanning & data analysis

Finally I am done with AFM scanning that took me to stay by 7 pm at the lab and then got locked out of the lab ๐Ÿ™‚ the keys don’t have access BTW! I had to call another grad to open the door for me to put the items back…

Anyhow, I am done with the data analysis and results did not come out as consistent as I expected! Kind of halfย  failure ! But still proved some stuff…

Let’s see how the poster prep goes…


Good luck all!

First Results on Gold Silica

Finally I have finished the data analysis on NanoScope software.

3 samples were analyzed, each had about 8-10 different locations scanned on both sides: Clean and dirty(No PDMS exposed and PDMS exposed).

Each scan has about 10-20 data regions and in total I had about 200+ data for each sample to work on statistics.

Goal is to compare the remaining residue on the surface to find out the best PDMS as a transfer agent, less residue is better!

4 approaches:

1- Raw data – no touch up

2- Statistical touch up: Mid 70% average; excluding first and last 15% range.

3- Finding the statistical frequency – probability distribution and according to the weighted regions of 70% finding the average.

4- Since #3 messed up on 10.0 /1 sample, I had to come up with the 4th approach, which is excluding the PDMS exposed regions if it is less than average of mid 70% of the clean side.

Boss liked the results and wanted to test more ๐Ÿ™‚

Prepared more polymers yesterday and they are curing in the incubator now!

Will analyze the data for SiO2 surface.


Week 3 – Terrible Wednesday!

So I was able to finish all measurements on Monday when I worked on the atomic force microscope(AFM) from 10 am to 4 pm, and just said

okay! Done! Now the rest is just data analysis!

And then participated to the weekly meetings with Dr. Natelson where he asked us to test samples on SiO2 surface besides the gold.

So we prepared the samples and I went to test them on AFM. First sample went ahead well… And then AFM started giving errors by lowering down the sampling rate to 0.1 Hz which results waiting 20-30 min for one scanning and I need to take about 10 measurements of the clean side and 10 of the PDMS exposed side.

So I kept replaced the tip, and normally I realized it when tip gets close enough for measurements (needs to be 10 to 80 micro meter )

And I just saw the tip scattered through the microscope AGGGHHHHH!!!!!


Sample needs to be replaced since it is full of junk on it now.

I could not continue since other tips did not work either….


Will continue on Monday. Lets see…


I attached two pictures of the surface for how it looks,… I am taking measurements for the roughness which is the equivalent of left over residues

Rio Grande Research for Water Testing


This is the link that was requested to be posted,


Students take measurements on Rio Grande River at different cities/ locations and then write journals… to compete.

Similar program can be established for Houston area water bodies…

Curing more PDMS – Different techniques

So we made our first samples and then tested them, results were good.

Initial AFM measurements came out as %0.06 residue left behind which was great!

Preparing the PDMS samples and keeping all other variables other than the mixing ratio is our new trial.

So prepared 3 more;

-At same time

– Stirred with magnetic rod and stage to keep all of them with same properties as possible

– Left in the incubator together at same time

Today I picked up the samples and they all look perfectly formed. Will test today.

Let’s see….




Polymer, gold evaporation on silicon film and atomic force microscopy

First week summary:

Day 1: Learned how to operate atomic force microscopy, how to insert nano tips for scanning which was pain in the neck since I was dealing with a very fragile 0.1 mm silica material.

Then my mentor showed me more lab equipment. We created our first polymer – PDMS which is formed by mixing two materials.

Since the materials are stirred, there are billions of bubbles!

We placed the polymer in a vacuum where it is applied under low pressure to surface bubbles, and then shocked with nitrogen gas to break bubbles, repeated the procedure about 7-10 times to have super smooth surface that will be used under AFM.

Placed in an incubator to speed up curing process whihc will take about 36 hours.

Day 2:ย  Got a silica glass film, and placed gold pieces at the bottom, super vacuum and high voltage applied to evaporate gold on silica film. Super shiny, nice looking gold mirror created!

Double sided tape can be seen where the clear part was behind the glass and other parts were also coated with gold and titanium.

Took the gold coated glass to atomic dicing machine to create 5 mm by 5 mm pieces that polymers will be placed on this to be analyzed under AFM.

Cleaned these pieces with sulfuric acid to remove all residues, any tiny dust particle will cause fluctuations.

Day 3: Researched about polymers, best mixing ratio, and how & where to buy.

Created two more polymers with the ratio of 9.1./1 and 10.1/1 to see the best result. I did this part on my own!

Yaaayy! ๐Ÿ™‚

Everything is super sensitive! 0.1 grams will mess up all!

Vacuumed to pop millions of bubbles and placed in incubator.

Next step is to place our first sample under AFAM and start taking data to be analyzed.