Nanostructure of polystyrene-b-poly(2-hydroxyethyl methacrylate) and derivatives with phosphonic diacid groups

Abstract

A engenharia de superfícies para o posicionamento de biomoléculas é uma etapa fundamental para a produção de biochips. Neste estudo, descreve-se uma nova estratégia para a preparação de nanodomínios contendo grupos ácido fosfônicos, os quais se ligam a uma família de proteínas (anexinas), de forma reversível em função da presença de íons cálcio. A abordagem desenvolvida consistiu no uso de precursores de poliestireno-b-poli(metacrilato de 2-hidroxietila) (PS-b-PHEMA) sintetizados por polimerização radicalar por transferência de átomos (ATRP) para a obtenção de cilindros de PS (f PS = 0.25-0.27) dispostos em morfologia hexagonal numa matriz de PHEMA. Os grupos hidroxila pendentes do PHEMA foram, em seguida, parcialmente (20%) convertidos em grupos ácido fosfônicos por reações sequenciais de fosforilação, sililação e metanólise. Este processo produziu derivados PS-b-P(HEMA-co-PEMA) que retêm a morfologia hexagonal, embora o grau de organização estrutural seja menor em relação aos precursores.Surface engineering for precise positioning of biomolecules is of particular interest for controlled fabrication of biochips. In this study, a novel approach for the preparation of nanodomains with phosphonic diacid groups that were previously shown to reversibly bind to a family of proteins (annexins) in a calcium-dependent manner is described. The strategy makes use of polystyreneb-poly(2-hydroxyethyl methacrylate) (PS-b-PHEMA) precursors prepared by atom transfer radical polymerization (ATRP) to obtain hexagonally packed PS cylinders (f PS = 0.25-0.27) in a PHEMA matrix. The pendant hydroxyl groups of PHEMA are then partially (ca. 20%) converted into phosphonic diacid groups via sequential reactions involving phosphorylation, silylation and methanolysis. This process produces PS-b-P(HEMA-co-PEMA) derivatives that still retain the hexagonal morphology, but their degree of structural organization is reduced comparatively to the precursors.

Ternary Phase Behavior of a Triblock Copolymer in the Presence of an Endblock-Selective Homopolymer and a Midblock-Selective Oil

“…In the latter case, however, the second reflection (at √3) is missing. Absence of this signature peak is attributed to the presence of an overlapping minimum in P ( q ), which is responsible for a marked reduction in Bragg peak intensity. , These two compositions are selected for discussion here because the overall PS fraction in each blend is similar (∼31 wt %). Since the densities of the EP midblock and MO are comparable (∼0.84 g/cm 3 ), the overall volume fraction of PS in both systems is nearly identical (∼27 vol %).…”

A Reactive Platform Approach for the Rapid Synthesis and Discovery of High χ/Low N Block Polymers

“…Incorporation of silicon-containing functionalities into block polymers containing poly(styrene) is typically observed to increase immiscibility with poly(styrene), 25,37,38 thus motivating TMS side-chain functionalization. DMAP, 2OH, and 4OH side chains were chosen to assess the extent to which terminal polar groups such as 3°amines and 1°a lcohols 39,40 increase χ eff to induce block polymer self-assembly.…”

“…Incorporation of silicon-containing functionalities into block polymers containing poly­(styrene) is typically observed to increase immiscibility with poly­(styrene), ,, thus motivating TMS side-chain functionalization. DMAP , 2OH , and 4OH side chains were chosen to assess the extent to which terminal polar groups such as 3° amines and 1° alcohols , increase χ eff to induce block polymer self-assembly. In order to tease apart the possible role of hydrogen-bonding interactions in driving possible microphase separation in 2OH and 4OH , we also investigated 2OMe in which the free hydroxyl functionality is capped with a methyl group.…”