We show that hydrophobic flexible polyelectrolyte molecules of poly(2-vinylpyridine) and poly(methacryloyloxyethyl dimethylbenzylammonium chloride) are trapped and frozen due to adsorption on the mica surface, and the observed AFM single molecule structures reflect the molecular conformation in solution. An increase of the ionic strength of the solution induces the cascade of abrupt conformational transitions due to the intrachain segregation from elongated coil to compact globule conformations through intermediate pearl necklace-globule conformations with different amounts of beads per chain. The length of the necklaces and the number of beads decrease, while the diameter of beads increases with the increase of ionic strength. Coexistence at the same time of extended coils, necklaces with different amounts of beads, and compact globules indicates the cascade of the first-order-type phase transitions.

The structure and dynamics of the "strong" glass of poly(n-decyl methacrylate) (PnDMA) have been studied, respectively, with X-ray diffraction and dielectric spectroscopy, dynamic light scattering, and rheology at temperatures below and above the glass transition temperature Tg ∼ 215 K. We find three dielectrically active processes, starting from low temperatures: (i) the γ-relaxation deep into the glassy state (with an activation energy of 5.7 kcal/mol), (ii) the "fast" β-relaxation just above the calorimetric Tg, with an activation energy of 11.4 kcal/mol, and (iii) the mixed Rβ-relaxation which has many similarities to a single R-process. Dynamic light scattering also identified the last two processes. The distribution of relaxation times for the Rβ-relaxation exhibits a strong T dependence ranging from a Kohlraush-Williams-Watts (KWW) parameter of 0.25 at Tg to about 0.7 at Tg + 115 K. This strong T dependence, which is a common feature of poly(n-alkyl methacrylates) with long side chains, reflects the contributions from concentration fluctuations from the PMMA-like backbone and the PE-like side chain. We compare our structural and dynamic results with those from the other members of the poly(n-alkyl methacrylates) series. There is a pronounced dependence of the fragility or steepness index on the length of the alkyl side chain. We found that this dynamic property has its origin on the low van der Waals peak (LVDW) of the static structure factor and reflects mainly differences in intersegmental distances and packing.

Membrane shapes, produced by dynamically assembled lipid/protein architectures, are crucial for both physiological functions and the design of therapeutic nanotechnologies. Here we investigate the dynamics of lipid membrane-neurotrophic BDNF protein complexes formation and ordering in nanoparticles, with the purpose of innovation in nanostructure-based neuroprotection and biomimetic nanoarchitectonics. The kinetic pathway of membrane states associated with rapidly occurring nonequilibrium self-assembled lipid/protein nanoarchitectures was determined by millisecond time-resolved small-angle X-ray scattering (SAXS) at high resolution. The neurotrophin binding and millisecond trafficking along the flexible membranes induced an unusual overlay of channel-network architectures including two coexisting cubic lattices epitaxially connected to lamellar membrane stacks. These time-resolved membrane processes, involving intercalation of discrete stiff proteins in continuous soft membranes, evidence stepwise curvature control mechanisms. The obtained three-phase liquid-crystalline nanoparticles of neurotrophic composition put forward important advancements in multicompartment soft-matter nanostructure design.

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