I am using a commercial PS nanosphere (60-70 nm) dispersion in water.
The dispersion is diluted in ethanol before injection into Langmuir-Blodgett trough (the stock concentration is 101 mg/ml).
All the samples I have prepared so far have been multi-layered.
What am I doing wrong?
Is it the original dispersion stabilizer (surfactant) incompatibility with ethanol or is it just the wrong concentration I am using?
I have tried adding Tween 20 and sodium dodecyl sulfate (SDS) but they failed in ethanol (e.g leading to a non-homogenous dispersion).
I also extended the sonication time of my diluted dispersion before each run up to 30 minutes but in vain.
Regarding the concentration, when I use low concentrations (as low as 1 mg/ml) the surface pressure (SP) does change during the compression of barriers.
Thanks in advance for sharing your valuable experience.
Dear Dr Jordan,
Thank you for your answer but due to the project constraints, currently, I cannot use any other techniques.
Few studies synthesized PS and diluted it in METHANOL before using it in LB process while some studies reported using ethanol (with different sizes of commercial PS).
It seems it can be related to PS, itself, as it can be soluble in ethanol as mentioned in the attached file.