Polystyrene-poly(methacrylic acid) block copolymer micelles

Abstract

Block copolymer micelles formed by diblock and triblock copolymers of styrene and methacrylic acid were characterized in solution in a mixed solvent with 80 vol % of dioxane and 20 vol % of water. Methods of static light scattering, quasielastic light scattering, differential refractometry, viscometry, sedimentation velocity, and densitometry were used. No unattached unimer molecules were observed. Three independent methods were employed for obtaining micellar weights. They agreed well with each other. No anomalous behavior was observed by any method. The micellar solutions were shown to contain almost exclusively single micelles; only a few samples (those producing the largest micelles) contained micellar clusters. The micelles behaved hydrodynamically and thermodynamically as impermeable spheres. The structure of the micellar shell was characterized in some detail. Relations between the aggregation number and the hydrodynamic radius of the micelles on the one hand and the sizes of the styrene and methacrylic acid blocks on the other were presented as scaling type phenomenological equations.Physicochemical properties of self-assembling molecules are of ever increasing experimental and theoretical interest. This is not only due to the intriguing phenomenon of selfassembling but also due to important applications of such materials in coatings, adhesives, thin films, microfabrication of electronic devices, pharmaceutical and photographic technologies, oil recovery, etc. Among the most important self-assembling systems are polymeric micelles.

Polyion complex micelles as vectors in gene therapy – pharmacokinetics and in vivo gene transfer

“…The sizes of the particles are much smaller than those measured by dynamic light scattering ( Table 1). As is often the case with polymeric micelles composed of dense core surrounded by solvated and expanded shell, 28 this apparent discrepancy may be due to the core-shell architecture of the PIC micelles. Since the PEG portion of the PIC micelles may not be stained with uranyl acetate, the particles in the picture of electron microscopy show only the core portion of the micelles.…”

Self‐assembled, wormlike‐cylinder network of polystyrene‐block‐poly(ethylene oxide) micelles in solution

“…[1][2][3][4][5][6][7][8] A wide range of micelle morphologies of block copolymers in solutions have been recently reported, and these morphologies possess better stability than those formed by small-molecule amphiphiles such as surfactants. [9][10][11][12][13][14][15] These block copolymer micelles can be potentially used in specific biological and medical applications.…”

Recent Research Progress in the Synthesis and Properties of Amphiphilic Block Co-polymers and Their Applications in Emulsion Polymerization

“…However, in most cases star block polymers aggregate into larger micelles, unimolecular micelles formed in water are very difficult to obtain. It turned out that the aggregation number of star amphiphilic block co-polymers was dependent on the number of arms: the greater the number of arms, the lower the aggregation number [53]. Further developments for multi-arm star structures amphiphilic block co-polymers are as follows: the synthetic and purification techniques of multi-arms star amphiphilic block co-polymers, systematic studies of micellar behavior of multi-arm star amphiphilic block co-polymers in aqueous media, further investigation of the mechanism of stabilization in emulsion polymerization.…”

“…In analogy to classic low-molecular-weight surfactants, the hydrophilic blocks can be classified as three categories by the sign of the electrical charge of the hydrophilic blocks: the non-ionic blocks, such as PEO [52], the anionic blocks, such as PAA [18], PMAA [53], poly(styrene sulfonate) [25,54] and poly(2-acrylamido-2-methylpropanesulfonic acid) [8], and the cationic blocks, such as poly(3-acrylamidopropyltrimethylammonium chloride) [8] and poly(vinylbenzyltriethylammonium chloride) [34].…”