2
$\begingroup$

I am looking for compounds that are liquid at normal temperatures and are physically very large, to be used in an ellipsometer adsorption experiment. I am currently working with decane. The candidates will ideally not be toxic or radioactive (such as $\ce{UF6}$).

$\endgroup$
  • $\begingroup$ What about solutions of proteins? Human serum albumin or something even larger? $\endgroup$ – Todd Minehardt Jun 16 '17 at 12:38
  • 1
    $\begingroup$ You need a molecule with weak intermolecular forces and low symmetry. $\endgroup$ – gsurfer04 Jun 16 '17 at 13:27
  • 1
    $\begingroup$ en.wikipedia.org/wiki/Polydimethylsiloxane ? $\endgroup$ – Mithoron Jun 16 '17 at 13:49
  • 1
    $\begingroup$ Dick - what are you looking for the molecule to do in your experiment? Provide the largest change per molecule in psi and delta, or what? Presumably a visible ellipsometer, not IR or UV? $\endgroup$ – Jon Custer Jun 16 '17 at 13:51
  • 1
    $\begingroup$ Look for liquid crystal molecules, many are large, for example those based on porphyrins. $\endgroup$ – porphyrin Jun 16 '17 at 19:03
4
$\begingroup$

You may give porphyrins a try. These dyes are of interest for molecular electronics, and to render them less crystalline / more glassy, alkyl chains are attached to the central motif. One recent example are the room temperature liquid porphyrins developed in the group around professor Gryko:

enter image description here

(source, Chem Asian J. 2010, 5, 904-909; doi: 10.1002/asia.200900693.)

Besides standard spectroscopic characterisation, the publication contains the results of DSC:

enter image description here

so compound 4d ($\ce{C176H294N4O12}$) may be a good candidate for an organic molecule, without charges and metal coordination, and suitable for ellipsometry / VASE measurments on surfaces.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.