10.1021/ma062617s.s001 Coleen Pugh Coleen Pugh Chau N. Tang Chau N. Tang Marta Paz-Pazos Marta Paz-Pazos Om Samtani Om Samtani Adam H. Dao Adam H. Dao Correlation of Free Radical Copolymerization Behavior and Copolymer Properties with the Strength of π−π Stacking Interactions between Aromatic Fluorocarbons and Aromatic Hydrocarbons:  Copolymerization of Styrene and Fluorinated Styrenes at the Two Extreme Levels of Fluorination American Chemical Society 2007 copolymers NMR spectroscopy results ethylene glycol contact angles Free Radical Copolymerization Behavior copolymerization styrene St bulk 4 FS rStrFS PFS 2007-11-13 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Correlation_of_Free_Radical_Copolymerization_Behavior_and_Copolymer_Properties_with_the_Strength_of__Stacking_Interactions_between_Aromatic_Fluorocarbons_and_Aromatic_Hydrocarbons_Copolymerization_of_Styrene_and_Fluorinated_Styrenes_at_the_Two_Extreme_Lev/2975083 In order to determine if the alternating tendency of styrene with fluorinated styrenes in free radical copolymerizations correlates with the strength and/or extent of π−π stacking interactions between aromatic fluorocarbons and aromatic hydrocarbons, styrene (St) was copolymerized with 2,3,4,5,6-pentafluorostyrene (PFS) and 4-fluorostyrene (4FS) under a variety of conditions. For the copolymerization of styrene with PFS at 25 °C, <i>r</i><sub>St</sub><i>r</i><sub>FS</sub> = 0.048 and 0.069 in bulk and toluene, respectively, using <i>tert</i>-butylperoxy pivalate as the initiator. For the copolymerization of styrene with PFS at 70 °C using benzoyl peroxide as the initiator, <i>r</i><sub>St</sub><i>r</i><sub>FS</sub> = 0.17 in bulk and <i>r</i><sub>St</sub><i>r</i><sub>FS</sub> = 0.14 in toluene. For the copolymerization of styrene with 4FS, <i>r</i><sub>St</sub><i>r</i><sub>FS</sub> = 0.69 at 25 °C under redox conditions and <i>r</i><sub>St</sub><i>r</i><sub>FS</sub> = 0.62 at 70 °C in bulk. As confirmed by <sup>1</sup>H, <sup>13</sup>C, and <sup>19</sup>F one-dimensional NMR and <sup>1</sup>H−<sup>13</sup>C heteronuclear single quantum coherence and <sup>1</sup>H−H nuclear Overhauser effect two-dimensional NMR spectroscopy results, St and 4FS tend to form random copolymers whereas the St-PFS copolymers tend to alternate with the alternating tendency increasing with decreasing temperature. The glass-transition temperatures determined by differential scanning calorimetry of the St-PFS copolymers are elevated relative to their mole-average values, whereas those of the corresponding homopolymer blends and the St-4FS copolymers occur at mole-average values. The water and ethylene glycol contact angles of both the St-PFS and St-4FS copolymer films occur at their mole-average values.