Fig. 2. Anticipated inter- and intra-chain interactions supported by through-space two-dimensional NMR measurements and ATR FT-IR analysis.
a Inter- and intrachain interactions due to side groups and copolymer backbone in p(MMA/nBA); inter-/intra-CH3b–CH2b are represented by a′ and a″ resonances at 1.62 and 0.96 ppm, respectively; inter-/intra-CH3m–CHb are represented by b′ and b″ resonances at 2.11 and 1.28 ppm (intensity changes of a′, a″, b′, and b″ resonances in NMR experiments are listed in Supplementary Table 4). 2D NOESY 1H NMR spectra of p(MMA/nBA: b undamaged, c air-cut/air-healed (0 min); d air-cut/air-healed (120 min); e air-cut/water-healed (120 min); f NOESY cross-peak intensities of CH3m–CHb (a′, a″) (curve a) CH3b–CH2b (b′, b″) (curve b), and undamaged (curve c) resonances as a function of time for air-cut/water-healed specimens. All resonances were normalized to α-methyl-CH3 and the -OCH3 proton cross-peaks at 3.61, 0.87 ppm (not shown) due to MMA units. g ATR-FTIR spectra of damaged p(MMA/nBA) copolymer exposed to water for 0 (a), 30 (b), 60 (c), 90 (d), 120 (e), and 150 (f) min.