Micellization of block copolymers

TL;DR: A general overview of the preparation, characterization and theories of block copolymer micellar systems is presented in this paper, with examples of micelle formation in aqueous and organic medium are given for di-and triblock copolymers, as well as for more complex architectures.

About: This article is published in Progress in Polymer Science.The article was published on 2003-07-01 and is currently open access. It has received 1856 citations till now. The article focuses on the topics: Micelle & Radical polymerization.

Figures

Table 1 (continued)

Fig. 1. Synthesis of block copolymers with ABC sequences (see text).

Fig. 9. Star–block copolymers: schematic representation of micellar structures for polystyrene (S)-polyisoprene (I) copolymers.

Fig. 4. CMC determination in aqueous medium of PS–PEO diblock copolymers labelled at the junction of the two blocks with an anthracenyl as ‘acceptor’ group, respectively a phenanthrenyl as ‘donor’ group. Fluorescence intensity ratio If (A)/If (D) (in arbitrary units) versus the copolymer concentration in mg/l. Excitation at 299 nm. If (A) determined at 370 nm and if (D) determined at 425 nm then Curve (a): PS–Anth– PEO, Mn ¼ 28 000 (43 wt% PS); PS–Phen–PEO, Mn ¼ 25 000 (40 wt% PS); equimolar ratio, CMC ¼ 0.4 mg/l. Curve (b): PS–Anth–PEO, Mn ¼ 114 000 (7 wt% PS); PS–Phen–PEO, Mn ¼ 114 000 (7 wt% PS); equimolar ratio, CMC ¼ 20 mg/l.

Fig. 3. Surface tension in mN/m versus the number n of consecutive measurements on the same copolymer solution. Aqueous solution of a PMMA10 2 PEO68 diblock copolymer (Mn ¼ 4000) at an initial concentration of 112 mg/l; first measurement (Wilhelmy plate technique) after an equilibration time of 6 days.

Fig. 11. (a) Surface modification of solid surfaces by block copolymers and block copolymer micelles. (b) Surface modification of solid surfaces by functionalized block copolymers and functionalized block copolymer micelles.

Table 6 Micellization of hydrophilic–hydrophilic A–B diblock copolymers containing at least one non-ionic sequence

Fig. 10. Schematic micellar structures of PIC.

Table 7 Micellization of hydrophilic–hydrophilic A–B diblock copolymers containing two ionic sequences

Fig. 5. Reversible micellization of hydrophilic–hydrophilic diblock copolymers under the influence of external stimuli, e.g. temperature, pH, electrolyte, etc. (schematic representation).

Table 3 Experimental techniques for micelle characterization

Fig. 6. Schematic structure of lamellar microcrystals (platelets) formed by controlled crystallization of PS–PEO or PB–PEO diblock copolymers. Crystallized PEO in the center of the platelets with a fringe of PS or PB solubilized in organic solvents, e.g. methylcyclohexane. (a) Self-assembly of crystallizable PS100PEO2500 diblock copolymer. Micrograph of platelets. Total size of the picture 200 £ 200 mm2.

Fig. 7. Micellization of PMMA-Pt BA in methanol, a selective solvent of Pt BA. Initiator end-group [I] effect on the diffusion coefficient D of the micelles. Schematic representation.

Fig. 2. Schematic representation of AB diblock copolymer micelles in a selective solvent of the A block. Rc : core radius; L : shell (corona) thickness.

Table 12 Scaling laws exponents: comparison of the experimental and theoretical values (micellization of PB–P2VP–PEO in water and n-heptane)

Table 10 Studies on AB and ABA block copolymer micellization in organic medium

Table 1 (continued)

Table 2 Poly A/poly B/poly C block copolymers with complex architectures—schematic structures

Fig. 8. Cross-linked micellar structures (schematic representation).

Table 8 Micellar characteristics of PB–PEO diblock copolymers in methanol at 20 8C

Fig. 11. (a) Surface modification of solid surfaces by block copolymers and block copolymer micelles. (b) Surface modification of solid surfaces by functionalized block copolymers and functionalized block copolymer micelles.