# Presentation: 845708

## Application of Dynamic Spectroscopic Methods to the Rheo-Optical Study of Polymers John F. Rabolt (University of Delaware) and Bruce Chase (DuPont)DMR 0315461

**Simultaneous PA-IR images and spectra obtained from 2-orthogonal polarizations (*****s***** and *****p*****) of IR light incident on a poly(ethylene terephthalate) (PET) film after cold drawing.  The increase in intensity of 1340 cm****-1**** “trans” band in *****p*****-polarized spectrum relative to 1375 cm****-1**** “gauche” band indicates both orientation and crystallization of PET during the drawing process.   Kinetics of the drawing process are amenable to the time scale of PA-IR.**

**Undeformed**

**Necked**

**s-polarized**

**p-polarized**

**p**

**s**

**1-D spatial images of deformed and necked region of PET film obtained simultaneously using the IR focal plane array (256x256 pixels) detector of the PA-IR instrument.  Spatial direction is vertical whereas the frequency is recorded in the  horizontal direction.   Simultaneously obtained spectra from the necked and undeformed regions show an increase in intensity of the 1340 cm****-1**** “trans” band in the former due to crystallization during drawing.**** **

**Trans**

**frequency**

**PET**

**frequency**

## Application of Dynamic Spectroscopic Methods to the Rheo-Optical Study of Polymers John F. Rabolt (University of Delaware) and Bruce Chase (DuPont)DMR 0315461

- We have organized a biweekly lecture class to teach graduate students the nuances of vibrational spectroscopy and the advantages that PA-IR spectroscopy offers in terms of studying dynamics in materials systems.  Attendance is currently open to the 60 graduate students in the MSE Department.  In addition to the fundamentals being discussed, numerous applications of PA-IR to “soft” and “hard” materials are explored.
- Since the DMA/PA-IR instrument has shown significant promise in our “real-time” studies of polymer deformation, Dr. Chris Snively, a Research Associate partially supported on this grant, developed a teaching/demonstration module for a graduate class, *Analytical Methods in Materials Science*. This module gives students a chance to compare and understand the concepts of single channel, multi channel and multiplex measurements.  Twenty-five students (graduate and upper undergraduate) from Materials Science and Engineering, Chemical Engineering and Chemistry took this course in F05.

**Outreach**
- Dr. Andrea Pesapane from the Politecnico Milano (working under Prof. Gus Zerbi in Materials Science) joined our research group for 6 months in March, 2006, in order to learn the DMA/PA-IR technique and characterize the dynamical behavior of polymers during molecular deformation. He will import this technique back to the group in Milan.
- Because of its uniqueness, the DMA/PA-IR technique has become very well known within the scientific community.  This has brought a number of visitors to our laboratory to carry out feasabilty studies on our prototype instruments. These include Dr. Andre Sommer (Dept. of Chemistry, Miami University, Miami,Ohio) who is Director of the Microspectroscopy Center and would like to couple a PA-IR instrument with a microscope, and Dr. Martin Schmidt/Dr. Michael Grunze (Jackson Laboratory, Bar Harbor, Maine) who are interested in adopting this technique for single cell spectroscopy.  In addition, two companies (Hologic and Nanoselect Sensors) have visited our laboratory and are exploring the use of PAIR instruments for quality control.

*Application of Dynamic Spectroscopic Methods to the Rheo-Optical Study of Polymers **John F. Rabolt (University of Delaware) and Bruce Chase (DuPont)**DMR 0315461*