Analysis of Styrene Polymerization Without Surfactant and N2 Gas in Cylindrical Flask.

Abstract

The conditions of chemical synthesis can be crucial for polymerization of styrene in such a way that it can be produced latex beads at nanometric range (ϕ < 400nm). In this work, it will be analyzed how the absence of N 2 and surfactant will result in colloidal particles with high affinity to agglomerate forming two kinds of nanostructured assemblies: colloidal crystals and nanowires. Four syntheses were realized and four parameters were changed: temperature, impeller speed, and initiator and styrene concentrations. The dispersion was filtered and coated on glass slides by evaporation induced selfassembly (EISA) process. Morphology and topography were observed at Scanning Electron Microscopy (SEM) and Atomic Force Microscope (AFM) respectively. They show how the synthesis conditions play a vital a role on the formation of self assembly nanostructures that can be applied as templates for sensors and biomaterials devices.

Morphoanatomy, floral biology and reproductive phenology of Cambuí (Myrciaria floribunda (H. West ex willd.) O. Berg.)

“…For the morphoanatomy analysis in scanning electronic microscopy (SEM), flower structure samples were separated and sections were manually performed, then metallized in gold evaporator (Quorum Technologies LTD, Ashford model Q 15 OR) for 10 minutes and finally taken to SEM (SILVA et al, 2018). Scanning electron photomicrographs were obtained using Shimadzu VEGA 3 LM-type coupled camera.…”

Geração de Filmes de Titânia meso-macroporosa por Modelagem de Esferas de Látex

“…Óxidos semicondutores têm sido aplicados em dispositivos funcionais a partir do uso de esferas de látex atuando como molde para a formação de uma rede de poros invertida (CARBAJO et.al., 2003;CHO et al, 2014;LI et al, 2005). Há relatos na literatura da aplicação de esferas de látex principalmente na preparação de óxidos Contudo, as esferas de látex não induzem porosidade na escala mesométrica o que só ocorre com uso de surfactantes como tem sido relatado na preparação de sílica e titânia mesoporosa (TIAN et al, 2008;SILVA et al, 2017). O uso de copolímeros como o P-123 na síntese de titânia mesoporosa resultou num material com estrutura cristalina e mesoporosidade definidas.…”