Chemists who synthesize ion-containing polymers must grapple with a severe hindrance - that of accurately measuring the molecular weight of their products. The lack of generally effective methods for determining this fundamental quantity retards research on ionic polymers, which find uses in water purification, energy conversion and storage, massive industrial scale electrolysis and other molecular separations. We are developing four methods that utilize easily measured dynamic properties of semidilute unentangled solutions of ionic polymers to obtain the number-average molecular weight Mn. Each method relies on specific combinations of calibrated measurements so that each method directly determines the number density of chains in solution and thus Mn. These four methods are insensitive to salt concentration and have the potential to enable routine molecular weight determination for ionic polymers, while using very little sample. We anticipate quick adoption of these methods, allowing rapid acceleration of the development and understanding of polyelectrolytes and ionomers to suit myriad applications.
Assist a graduate student in Prof. Colby's group, developing methods to characterize the molecular weight (chain length) of polyelectrolytes using a wide variety of instruments, including rotational rheometers that measure viscosity and relaxation time. WE ask that students commit 10 hours/week to work in the lab. All students are welcome (even Freshmen) and the sooner you join us, the more you can do!
Contact Prof. Ralph Colby and send your CV by e-mail to firstname.lastname@example.org