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Recent content by sandip179

  1. sandip179

    Streaking during spin coating

    The streaks emanate from the center of the substrate to the periphery. I dont think it is due to particles in the solution, as I filter the solution with a 0.7 micron filter. I apply the solution by covering the entire substrate with a thin layer of solution and then spin-coating. Reducing the...
  2. sandip179

    Streaking during spin coating

    I am spin coating a polymer solution in toluene (bp=110C). However, after spin coating, I see streaks of the polymer on the substrate. Any idea as to how to solve the issue? I have played with polymer concentration and speed without any effect.
  3. sandip179

    Different ways of Coating

    I am a recent college grad, and in my present job I am supposed to find out the best way to coat a 15" x 15" substrate with styrene butadiene rubber (SBR). Right now, we are spin-coating a solution of SBR in toluene, but in far smaller areas. Can spin coat work for larger areas like 12"x12" or...
  4. sandip179

    Polymer Cracking

    Thanks. Some of the SBR polymers I have tried exhibit the problem of cracking. What makes some polymers crack when they are spin-coated on another elastomer? Is it due to different hardness or Young's modulus? Any help in trying to understand the cracking issue would be highly appreciated.
  5. sandip179

    Polymer Cracking

    I require pretty strong resistance. I am talking of exposure of concentrated acids (30%) at 100C for 1-2 minutes. However the exposure is just one-time, and even if the polymer film partially survives one-time exposure, its ok. Btw, the idea of using hydrogenated SBS is great. I was just...
  6. sandip179

    Master fabrication

    I am new to the microfabrication business. I have a chrome mask which has features 1 to 10 microns wide and 10 microns high. Is there any place which would make a silicon master (3" dia) out of it?
  7. sandip179

    Polymer Cracking

    Hey, A butadiene styrene rubber (MW=38000) did work for my application. One thing is that the polymer is not very resistant to acids. Any idea as to how to improve its chemical inertness without modifying its properties?
  8. sandip179

    Polymer Cracking

    The function of the polymer is to act as acid resist on selected areas of the metallic substrate. It can be soft, but it should be soluble in a solvent so that it can spin or spray coated onto the elastomer. I am corono treating the elastomer for 30 s. that does not help. maybe i can treat it...
  9. sandip179

    Polymer Cracking

    the elastomeric material is cured PDMS (polydimethylsiloxane). The metallic substrate in question is smooth aluminium. Let me know if you need any more details.
  10. sandip179

    Polymer Cracking

    Let me state my entire application. I want to coat a thin layer of polymer on an elastomeric material, then transfer this polymer layer onto a metallic substrate. After some time I would like to remove the entire polymeric layer by washing or degrading it. It is not necessary for the polymeric...
  11. sandip179

    Polymer Cracking

    Thanks. Can you suggest any particular solvent soluble polymers that can be used? and where can I get them. I looked at the website of Sigma Aldrich, and didnt find anything worthwhile.
  12. sandip179

    Polymer Cracking

    I am trying to spin-coat a solution of PMMA (MW=15k) on a elastomeric material, but I find that the polymer cracks. Is there any polymer that wont crack? Or can I add any additive to my polymer to prevent cracking?
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