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The dimensions and intermolecular interactions of surface-grafted and unbound, free polyampholytes, poly [3-(N-2-methacryloyloxyethyl-N,N-dimethyl) ammonatopropanesulfonate] (PMAPS) and poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC), were estimated in an aqueous NaCl solution over a wide range of salt concentrations (C s ). The free PMAPS and PMPC fractionated by a recycling preparative size-exclusion chromatography system were characterized in aqueous NaCl solutions for C s over a range from 0 to 5.0 M by static light scattering and dynamic light scattering (DLS) measurements. The hydrodynamic radius (R H ) and the concentration coefficient of the diffusion coefficient (k D ) for PMPC were independent of C s , whereas those for PMAPS were strongly dependent on C s . Monodisperse silica nanoparticles immobilized with PMAPS (SiNP-PMAPS) and PMPC (SiNP-PMPC) by surface-initiated atom transfer radical polymerization were characterized in aqueous NaCl solutions for C s over a range from 0 to 5.0 M by DLS and synchrotron radiation small-angle X-ray scattering (SAXS) measurements. The SAXS profiles from SiNP-PMAPS and SiNP-PMPC solutions were well described by the core-shell model, taking into account interacting self-avoiding chains and assuming a Schulz-distributed core with two fitting parameters.

The relationships between the molecular aggregation states and water repellency of the perfluoroalkyl (R f ) groups of poly{2-(perfluorooctyl)ethyl acrylate} (poly-(FA-C 8 )) brush thin films with broad and narrow molecular weight dispersities (MWDs) were analyzed by grazing incidence wide-angle X-ray diffraction (GI-WAXD) and water contact angle measurements. MWD-controlled-poly-(FA-C 8 ) brush thin films were prepared by surface-initiated atom transfer radical polymerization on a flat silicon substrate in the absence and presence of an ionic liquid. In-plane diffraction profiles of poly(FA-C 8 ) brush films with narrow MWD had peaks corresponding to the periodic lengths of bilayer lamellae at q xy = 2−6 nm −1 . This indicated that the orientation of R f groups were parallel to the surface of the silicon substrate. In contrast, the peak of the in-plane GI-WAXD for brush films with broad MWD brush was confirmed at q xy = 12.5 nm −1 , indicating that the R f groups were oriented perpendicular to the surface of the silicon substrate. In the case of a poly(FA-C 8 ) brush thin film with a narrow MWD, the receding contact angle (θ R ) and sliding contact angle (θ S ) versus water were ca. 80°and 35°, respectively, whereas θ R and θ S were 105°and 15°, respectively, at the surface of poly(FA-C 8 ) with broad MWD. These results indicated that the water repellency of poly(FA-C 8 ) brush surface largely depends on the molecular aggregation state and orientation of the R f groups at the outermost surface and the MWD of the grafting polymer.

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Preparation of strong fiber with ultrahigh strength and modus is a dream of polymer scientists and engineers. It is believed that a shish-kebab is the structure origin of the ultrahigh strength and modulus fiber. This article presents our investigation on the inner structure of shish-kebab precursor of isotactic polystyrene in μm scale formed by shear flow above the nominal melting temperature T m using microbeam wide-and small-angle X-ray scattering (WAXS and SAXS). The microbeam WAXS experiments indicated that the precursor included crystallites with degree of crystallinity of ∼0.15%, which had higher melting temperature than normal lamellar crystals, meaning that its size (the length) was longer in the c-axis of crystals than the normal lamellar crystals. The microbeam SAXS experiments confirmed that approximately 1% of the crystallites in the precursor were rather long in the direction of c-axis. It is expected that such crystallites work as an initiator of a shish when it is below T m .

Synchrotron small-angle X-ray scattering (SAXS) at the SPring-8 40B2 and 45XU beamlines was carried out on aqueous solutions of (PEG-P(Asp(Bzl))): partially benzyl-esterified poly(ethylene glycol)-block-poly(aspartic acid) with LE540 loaded up to 8.3 wt %, where LE540 is a very hydrophobic retinoid antagonist drug. The scattering profiles showed characteristic features for core-shell spherical micelles, confirming that P(Asp(Bzl)) forms a hydrophobic core and PEG forms a hydrophilic shell. Before the addition of LE540, a diffraction peak was observed around q = 4 nm(-1), where q is the magnitude of the scattering vector. This peak can be attributed to ordering between alpha-helices made of P(Asp(Bzl)), the so-called nonspecific hexatic arrangement. The P(Asp(Bzl)) helices disappeared as LE540 was added. This result can be interpreted by assuming a uniform distribution of LE540 in the core. By use of a core-shell spherical micelle model, the SAXS data could be well fitted for all of the samples. The analysis indicated that the core radius increases sigmoidally from 5.9 to 6.9 nm upon addition of LE540 whereas the shell radius stayed at 12.5-12.8 nm. The aggregation number that is the average number of PEG-P(Asp(Bzl))'s consisting of one micelle slightly increased from 145 to 182.