Week 5

Viscosity Measurements. This week saw our first real data for the LiTFSI doped CmPyrrTFSI series with the viscosity measurements of the C6mPyrrTFSI over the 5-85C range. This measurement, unlike the conductivity liquid cell measurements, is not automatized and therefore requires constant observation which is a little taxing. Although most of our measurements were within the 0.2-200cP range of our piston, the 15C measurement was in the 300cP range, and the 5C measurement was too high for our viscometer to measure, even more incentive to invest in a new viscometer. I also prepared C4mPyrrTFSI with a 10:1 LiTFSI ratio that I am currently testing this week.

On the liquid cell front, we talked to two Agilent technical representatives who suggested we attempt to test the dielectric measurements using a Teflon spacer, given that Teflon has a consistent and well reported dielectric constant. They were also very surprised that we used the liquid cell to measure conductivity, they said ‘They had never heard of someone using the liquid cell for conductivity measurements’. This side comment has Allison very concerned that there is a specific reason why no other group has considered using the liquid cell for conductivity measurements. We also have decided to dissect one of the liquid cells to check for corrosion of the inside of the electrodes.

Karl-Fischer titrations. I have been in contact with a representative from Metrohm to get a quote on their various Karl-Fischer titration instruments. We are looking into this instrument for possible checking the water content of our reagents to ensure that they only have trace amounts of water. Although Metrohm’s instruments come already calibrated, we believe that we can design utilize one of our already instruments that already measures conductivity and use Karl-Fischer solution to pretty much do the same thing. This is especially becoming a more convenient solution given that our lowest quote for a stripped down demo version of one of Metrohm’s instruments is $6,000. Wes and I will probably look into more detail about the possibility of making an in-house Karl-Fischer titration next week.


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