Surface Characterization Results

Water contact angle measurement will be done on control and modified fibers to evaluate the hydrophilicity with help of a goniometer. Previous literature states that a decrease in water contact angle to 50o is an optimal improvement in hydrophilicity. For our pilot study, the ImageJ program was used to find the water contact angle on high resolution photos of the PCL fibers.  In January, a goniometer at GM will be used for more accurate contact angle measurement.

Contact Angle Results

 

An infrared spectrometer will be used to evaluate the modified film surface chemical composition by recognizing the functional groups that are present on the surface. On the IR spectrometer, the lens will be covered with the sample, and the spectrometer will pass infrared radiation through the sample at different wavelengths (2.5-15 µm). The computer composes a spectrum using the absorption of specific wavelength energies of the functional groups of the compound. We expect to see additional peaks in the functionalized PCL at 1650 and 1540 cm-1 indicating the presence of amide bonds.

ATR-FTIR Results

 

X-Ray Photoelectron Spectroscopy (XPS) determines the chemical composition of a surfaces top several nanometers. An electron energy analyzer determines the energy of emitted photoelectrons when the sample is exposed to a beam of x-rays. A photoelectron peak is then created with a unique binding energy and intensity that can quantify the functional groups on the polymer surface. Detection of nitrogen and carbons from C=O bonds means that RGD is present on the surface. XPS analysis will be done before and after treatment of PCL at Wayne State University.

XPS Results

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