Figure 5: Intermolecular field and nanoscale variation of coupling and dynamics.
(a) Modelled solvatochromic spectral shifts of the carbonyl resonance relative to the shift predicted for a molecular probe in bulk PS. Electric field and Stark shift are calculated for dielectric environments in PS (red), bulk PMMA (green)36 and PMMA nano-domains in a PS-PMMA blend (blue)29. The molecular probe is approximated using dielectric parameters for various tacticities of PMMA, syndiotactic- (circle), atactic- (x) or isotactic- (+) PMMA chains, as well as for shorter oligomer segments (trimer o3-PMMA) and monomer (o1-PMMA). Local s-SNOM measurement of spectral shift in domain centres relative to the interface for syndiotactic-PS-b-PMMA are indicated by black squares, with error bars calculated from the spectral distribution of peak positions in centre and interface. (b) Spectrally resolved line cut along the region indicated in Fig. 4 a,b showing local relative concentration of PMMA as measured by the s-SNOM phase (top colour map), linewidth (middle), and spectral shift (bottom), with derived local electric field F.
