NSRRC Activity Report 2022

078 NSRRC ACTIVITY REPORT 2022 Figure 2(a) 1 displays SANS profiles of PMMAzo-b-PEG-b-PMMAzo in d -DMF/D 2 O solvent 70:30 with varied KCl concentration. As presented in Table 2 , 1 the core radius marginally increased and the corona thickness considerably decreased when the KCl concentration was increased. This behavior was associated with the salting-out effect induced by KCl, which caused the dehydration of some ethylene oxide segments that were adjacent to the PEG/PMMAzo interface. The dehydrated ethylene oxide segments became hydrophobic and partly segregated into the micellar core, which resulted in an increased core radius. In contrast, the hydrophilic corona lost some dehydrated ethylene oxide segments, which caused a decreased corona thickness. In contrast to the salting-out effect induced by KCl, the solubility of PMMAzo segments in water increased upon the addition of KSCN. This effect facilitated their organization from the hydrophobic core to the hydrophilic corona in micelles and resulted in an increased corona thickness and a decreased core radius ( Fig. 2(b) and Table 3 ). 1 (Reported by Chieh-Tsung Lo, National Cheng Kung University) This report features the work of Chieh-Tsung Lo and his collaborators published in J. Mol. Liq. 348 , 118013 (2022). ANSTO QUOKKA – Small-angle Neutron Scattering • SANS • Polymer, Biomaterial, Drug Delivery, Soft Matter Reference 1. Y.-S. Wu, J.-Y. Ma, J. P. Mata, C.-M. Wu, K.-L. Hsu, C.-T. Lo, J. Mol. Liq. 348 , 118013 (2022). Fig. 2 : SANS profiles of PMMAzo-b-PEG-b-PMMAzo in d -DMF/D 2 O solvent 70:30 with varied concentration of (a) KCl and (b) KSCN measured at Quokka . [Reproduced from Ref. 1] Table 3: Structural parameters of PMMAzo-b-PEG-b-PMMAzo dissolved in d-DMF/D 2 O solvent 70:30 with varied KSCN concentration. [Reproduced from Ref. 1] KSCN concentration (M) R c (Å) R g (Å) R total (Å) n M 0 78.9 77.4 155.3 35.9 2.5 0.1 78.5 81.5 160.0 34.2 2.2 1.0 77.2 82.5 159.7 33.8 2.1 Table 2: Structural parameters of PMMAzo-b-PEG-b-PMMAzo dissolved in d -DMF/D 2 O solvent 70:30 with varied KCl concentration. [Reproduced from Ref. 1] KCl concentration (M) R c (Å) R g (Å) R total (Å) n M 0 78.9 77.4 155.3 35.9 2.5 0.1 79.1 66.7 145.8 48.0 2.3 1.0 80.0 45.7 125.7 48.7 2.3 Table 1: Structural parameters of PMMAzo-b-PEG-b-PMMAzo in various mixed solvents. [Reproduced from Ref. 1] d -DMF/D 2 O composition R c (Å) R g (Å) R total (Å) n M 70:30 78.9 77.4 155.3 35.9 2.5 50:50 95.7 54.4 150.1 121.6 2.7 30:70 97.4 52.1 149.5 134.6 3.0 R c : radius of micellar core; R g : thickness of micellar corona; R total : radius of micelles; n : association number of micelles; M : exponent of a power law.