Morphology of the first zoeal stage of the commensal southwestern Atlantic crab Austinixa aidae (Righi 1967) (Brachyura: Pinnotheridae), hatched in the laboratory

6 páginas, 2 figuras, 1 tabla.The first zoeal stage of the endemic southern Atlantic pinnotherid crab Austinixa aidae is described and illustrated based on laboratory-hatched material from ovigerous females collected from the upper burrows of the thalassinidean shrimp Callichirus major at Ubatuba, São Paulo, Brazil. The zoeae of Austinixa species can be distinguished from other pinnotherids and especially from zoeae of the closely related species of Pinnixa by the telson structure.FLM is grateful to CNPq for a research fellowship (Proc. 301359/2007-210 5).Peer reviewe

Rod-Like Nanoparticles with Striped and Helical Topography

The behavior of nanoparticles in solution is largely dominated by their shape and interaction potential. Despite considerable progress in the preparation of patchy and compartmentalized particles, access to nanoparticles with complex surface patterns and topographies remains limited. Here, we show that polyanionic brushes tethered to rod-like cellulose nanocrystals (CNCs) spontaneously develop a striped or helical topography through interpolyelectrolyte complexation with polycationic diblock copolymers. Using cryogenic transmission electron microscopy (cryo-TEM) and tomography (cryo-ET), we follow the complexation process and analyze the delicate 3D topography on the CNC surface. The described approach is facile and modular and can be extended to other block chemistries, nanoparticles, and surfaces, thereby providing a versatile platform toward surface-patterned particles with complex topographies and spatially arranged functional groups

Controlling the shape of Janus nanostructures through supramolecular modification of ABC terpolymer bulk morphologies

| openaire: EC/FP7/291364/EU//MIMEFUNBlock copolymers microphase separate into a variety of bulk morphologies that serve as scaffolds, templates, masks and source for polymeric nano-particles. While supramolecular additives are common to complex within diblock copolymers to modify the morphology, the subtle effects of complexation on ABC triblock terpolymer morphologies are less explored. Here, we describe the manipulation of polystyrene-block-poly(4-vinylpyridine)-block-poly(tert-butyl methacrylate) (PS-b-P4VP-b-PT or S4VT) triblock terpolymer bulk morphologies through supramolecular complexation with rod-like 4-(4-pentylphenylazo)phenol (5PAP). The 5PAP molecule hydrogen bonds by phenolic groups to the 4VP repeating units and with increasing molar fraction of 5PAP, initially observed P4VP cylinders flatten into elliptic cylinders until a morphological transition occurs into a third (P4VP/5PAP) lamella. At sufficient 5PAP loadings, the cylinders can even merge into a perforated P4VP lamella located at the PS/PT interface. Quaternization of the P4VP phase and re-dispersion in organic solvent allows liberating S4VT Janus nanostructures from the bulk, including Janus cylinders, nanoporous Janus membranes and Janus sheets. The manipulation of “sandwiched” microphases through supramolecular binding motifs could allow the preparation of previously inaccessible terpolymer bulk morphologies and, in case of cross-linkable phases, lead to a larger library of Janus nano-objects.Peer reviewe