[Fwd: New Chemical Request: Perfluorooctyl-trichloro-silane]

Mary Tang mtang at stanford.edu
Tue Feb 14 12:00:39 PST 2006

Oops.  I don't think we did answer it.  I think it's OK from a safety 
perspective, especially in the small amounts described here.  But I 
still do prefer the -ethoxy and -methoxy versions of these chemicals 
over the -chloro versions.  The only possible problems I see are that 
the dessicator will be coated with this anti-sticking stuff (is that a 
problem?  I'm not sure what else the dessicator is used for.  It will 
mean that if there is cross-contamination, the problem will be stuff not 
sticking to substrates) and that the -chloro versions of these compounds 
tend to react quickly with any moisture in the air to polymerize into 

My suggestion is that if we are concerned with cross-contamination that 
we have a dedicated dessicator for anti-sticking processes (as I also 
think that nanoimprint might need something like this anyway.)  It's a 
couple hundred dollars 
(http://www.jenconsusa.com/products_specs_1.cfm?id=26).  It might be a 
good idea to have one dessicator for hydrophobic processing and another 
for hydrophillic processes.


Mahnaz Mansourpour wrote:

> I am forwarding this to specmatt , not knowing if we have answered it 
> or not?
> mahnaz
> -------- Original Message --------
> Subject: 	New Chemical Request: Perfluorooctyl-trichloro-silane
> Date: 	Fri, 27 Jan 2006 17:04:01 -0800
> From: 	Neville Mehenti <nmehenti at stanford.edu>
> To: 	specmat at snf.stanford.edu
> CC: 	nmehenti at stanford.edu
>I would like to make a request to bring a new chemical into the cleanroom 
>for use in a process.
>Below this email is the requested information for this new chemical 
>request, as outlined on the SNF website.
>Please let me know if there is a problem or if you would like any more 
>Thanks very much and hope to hear from you soon.
>1.  Name: Neville Mehenti; Coral: mehenti; Tel: (650)723-1669; Email: 
>nmehenti at stanford.edu, PI: Prof. Stacey F. Bent
>2.  Full Name: 1H,1H,2H,2H-Perfluorooctyl-trichloro-silane (CAS 78560-45-9)
>The MSDS is attached with this email as a pdf file.
>3.  Manufacturer:  Sigma-Aldrich
>3050 Spruce Street, St. Louis, MO 63103; Tel: 314.771.5765; Website: 
>4.  The reason I am requesting to bring this material into the lab is 
>because I am looking to spin thin (10-20 microns) silicone membranes on a 
>silicon-photoresist mold, and then peel them off to serve as components for 
>microfluidic devices.  I have been using polydimethylsiloxane (PDMS) as the 
>membrane material, but the membranes are not strong enough to resist 
>tearing or stretching upon removal from the mold.  I have found that 
>treatment of these molds by exposing them to this requested chemical under 
>vacuum allows for easier release of the membrane from the mold with minimal 
>stretching.  By silanizing the silicon-photoresist mold with this chemical, 
>the surface of the mold is effectively "teflonized," thus preventing any 
>strong interaction between the PDMS and the mold.  I would prefer to do 
>this process at the fab so that my molds remain in a clean environment 
>(since I have had particulate problems when silanizing in my normal lab and 
>this creates several problems with the resulting membranes).
>5.  I plan on using this chemical only in the desiccator above the 
>Headway.  I will place my silicon photoresist molds along with a small 
>volume (~100 microliters) of the chemical in the desiccator and pull house 
>vacuum on it for one hour, thus forming silane vapor which will 
>subsequently react to the native oxide on the mold.  I will then spin PDMS 
>on these molds using the Headway, and they will then require no further 
>processing within SNF.
>6.  For each time I silanize my molds, I will be using ~100 microliters of 
>this chemical, which is in liquid form.  Only a small fraction of this 
>volume will be vaporized to properly silanize the surface of my molds.
>7.  I will carefully bring in the appropriate volume (~100 microliters) of 
>the chemical into SNF each time I need to use it.  The chemical will be 
>stored in a labelled 1-ml glass vial, and will be brought in within a 
>larger vial as a secondary container.  When placed in the desiccator, I 
>will remove the cap from the vial and place the vial in one of my beakers 
>(in order to stabilize the vial from falling due to a bump or rapid 
>pressure changes).
>8.  After the silanization process, I will put the cap back on the vial, 
>and place this vial back in the secondary container.  These vials will be 
>removed from the fab and I will dispose of it properly within my regular 
>lab as hazardous waste. 

Mary X. Tang, Ph.D.
Stanford Nanofabrication Facility
CIS Room 136, Mail Code 4070
Stanford, CA  94305
mtang at stanford.edu

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