Isotactic polystyrene INDEX

First Polymer Series. The first series of polymers was investigated, in order to limit the interaction between an AFM probe and polymer surfaces to only the dispersion (London) component of the Van der Waals force. Adhesional forces were measured between a S10,t probe and a set of nonpolar polymers that provided a range of refractive indexes (as measured) polystyrene (1.582), isotactic polypropylene (1.501), poly(vinylidene fluoride) (1.407), and poly(tetrafluoroethylene-co-hexafluoropropylene) (1.348). The histograms of the pull-off forces, measured with a SiOx probe, are shown in Figure 2 and tabulated with the calculated values for adhesion energy in Table 1. 

Non-Polar Polymers. The ability to distinguish between polymers of differing refractive index was tested 10) by measuring pull-off forces between a silica tip and a series of four non-polar polymer samples in perfluorodecalin (a non-polar, low-refractive-index liquid, =1.317) polystyrene (PS, =1.582), isotactic polypropylene... 

The isotactic polypropylene and polystyrene were obtained from The Dow Chemical Company. The PP used was Dow ZN5D98 having a bulk density of 0.900 g cm and melt flow index of 3.4 g per 10 min. The PS used was Dow STYRQN 685D having a bulk density of 1.040 g cm and melt flow index of 1.5 g per 10 min. 

---