How Can I Even Out My PMMA Structures Through Heating or Annealing?

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Discussion Overview

The discussion revolves around methods for evening out PMMA structures created through thermal imprinting. Participants explore the effects of heating and annealing on the PMMA samples, which have specific dimensions and structural features. The focus is on finding optimal heating parameters to achieve the desired surface characteristics without damaging the material.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant suggests annealing the PMMA at 150 degrees Celsius for 2 hours to allow the material to soften and potentially even out the structures.
  • Another participant proposes a much higher temperature of 1200 degrees Celsius for a very short duration, although this approach lacks detail on its feasibility.
  • A participant shares experimental results from heating PMMA at 500 degrees Celsius for varying durations, noting that while 15 seconds did not damage the material, longer durations resulted in destruction.
  • Another experiment involved heating at 160 degrees Celsius for 1½ hours, which led to significant reshaping of the PMMA, indicating that longer low-temperature exposure may be more effective.
  • One participant questions the necessity of sharp points in the structures and suggests alternatives like polishing or etching to achieve shallower grooves.
  • A later reply acknowledges the impracticality of polishing to the required depth and suggests that controlled chemical etching or reactive ion etching might be viable alternatives if protective coatings are applied.

Areas of Agreement / Disagreement

Participants express differing opinions on the best approach to modify the PMMA structures, with no consensus on the optimal heating parameters or methods. Some propose annealing while others suggest alternative techniques like etching.

Contextual Notes

Participants mention various experimental outcomes, but there are unresolved questions regarding the optimal conditions for heating and the effectiveness of alternative methods like etching. The discussion reflects a range of experiences and hypotheses without definitive conclusions.

Zamot40
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I made some structures in PMMA and now I would like to even them out a little bit. The structures are made with thermal imprint and are 150 nm deep and with a period of 300 nm, which is the smallest stamp we have at the university, I could of course make a new stamp, but that would take a lot of time.

Right now I am considering annealing of the samples to make them soft and give it a long time in the oven and the PMMA will float a bit. eg. 150 degree celsius for 2 hours.

I have also considered heating the oven to 1200 degree celsius and give it a short time, eg. 5 minutes.

If anyone has some experience or knowledge of this I would be happy
 
I'd love to help you, but I have absolutely no idea of what the hell you're talking about. :s
 
okay maybe I don't not make myself clear enough. I made a drawing of what has been done to the PMMA and what I want to do with it. Maybe it looks a

bit odd due to the imgur upload. We have some PMMA with structure in it and then I want these structures to shrink and I thought heating them in the oven would soften the structures out. I did some testing in the lab with PMMA in the oven at 500 degree celsius for 5 seconds to 1 minute. The ones at 1 minute are totally destroyed, but 15 seconds seemed to not make any damage to the PMMA, however the somewhat larger scratches were not softened either.
I also tried 1½ hour in the oven at 160 degree, but this just reshaped the PMMA totally.
Now I am thinking the long duration low temperature is the best way to go, but It would take a long time to find the optimal parameters so I would really like some help here.
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I'm sorry, but I didn't make my previous post clear enough. I didn't mean that you posted a bad question; it's just that I know nothing about the subject. Someone else will have to help you. I just responded so you wouldn't feel ignored.
 
Are the sharp points necessary? You could polish or etch the surface and the grooves would be shallower.

BoB
 
No the sharp points are not necessary. You make a good point, but polishing only ~75 nm is practicly impossible with the tools we have at the university. Some form of well controlled chemical etch might do the job. Reactive ions etching could work if I could coat the grooves with a thin layer of some protecting material I suppose.
 

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