Triblock copolymer schematic

Thermoplastic Elastomers. These represent a whole class of synthetic elastomers, developed siace the 1960s, that ate permanently and reversibly thermoplastic, but behave as cross-linked networks at ambient temperature. One of the first was the triblock copolymer of the polystyrene—polybutadiene—polystyrene type (SheU s Kraton) prepared by anionic polymerization with organoHthium initiator. The stmcture and morphology is shown schematically in Figure 3. The incompatibiHty of the polystyrene and polybutadiene blocks leads to a dispersion of the spherical polystyrene domains (ca 20—30 nm) in the mbbery matrix of polybutadiene. Since each polybutadiene chain is anchored at both ends to a polystyrene domain, a network results. However, at elevated temperatures where the polystyrene softens, the elastomer can be molded like any thermoplastic, yet behaves much like a vulcanized mbber on cooling (see Elastomers, synthetic-thermoplastic elastomers). 

Figure 3.8. Schematic representation of the polystyrene domain structure in styrene-butadiene-styrene triblock copolymers. (After Holden, Bishop and Legge )...

Fig. 57 Schematic comparison of chain conformations of the midblock for ABC and ABA triblocks. ABC triblock terpolymers (a) have bridge conformations only, whereas ABA triblock copolymers (b) have bridge and loop conformations. From [159]. Copyright 2002 Wiley...

Fig. i Schematic representation of chain conformation in micelles from a linear PEO-PBO diblock copolymers, b linear PEO-PBO-PEO triblock copolymers, c linear PBO-PEO-PBO triblock copolymers and d cyclic PEO-PBO diblock copolymers... 

Fig. 18 Schematical representation of different types of micelles formed by ABC triblock copolymers. Core-shell-corona micelles with insoluble core and shell (a), core-shell-corona micelles with radially compartmentalized corona (b), and Janus micelles with laterally compartmentalized corona (c)...

Fig. 19 TEM image of toroidal micelles from a PAA-PMA-PS triblock copolymer (A). This sample was cast from a solution with 0.1 wt% PAA99-PMA73-PS66 triblock copolymer, a THF water volume ratio of 1 2, and an amine acid molar ratio of 0.5 1 by addition of 2,2-(ethylenedioxy)diethylamine. The cast film was negatively stained with uranyl acetate. A schematical representation of theses micelles is also shown (B). Reprinted with permission from [279], Copyright (2004) American Association for the Advancement of Science...

Scheme 12 Schematic representation of the synthetic procedure that was applied for the preparation of three triblock copolymers with the same first and second blocks...

Figure 1. Schematic of self-assembly assisted polypolymerization (SAAP) of triblock copolymers in a selective solvent for the synthesis of long multiblock copolymers with a controllable chain sequence and block length. [3 5]...

Figure 11.27 Schematic representation of the hexagonal columnar structure of an ABA triblock copolymer with a G1 dendron and the body-centered cubic stmcture of an ABA triblock with a G2 dendron.

Figure 14.10 TEM image of blend containing 75 wt. % of a SBT triblock copolymer and 25 wt. % st diblock co-polymer. The non-centrosymmetric supramolecular structure of this blend is schematically illustrated in the diagram that assigns the different phases observed in the marked part of the micrograph (Copyright Wiley-VCH Verlag GmbH Co. KGaA. Reproduced by permission).

Fig. 10 Schematic depiction of bridge chain and loop chain configurations in cylindrical morphology from the ABA triblock copolymer self-assembly...

FIGURE 3-34 Schematic representation of the formation of a styrene/butadiene (SBR) triblock copolymer by living anionic polymerization. 

Figure 10 Examples for phase segregate microstructures in ABC triblock copolymers. Transmission electron micrograph and schematic three dimensional representation of (a) the knitting pattern morphology [107], Reproduced from [107] with permission of Huthig Wepf Verlag.

Fig. 15.8. Schematic depiction of the approach to generate nanotubes using triblock copolymers. (Adapted from [39].)...

Fig. 2. Schematic of connecting chains at an interface, a diblock copolymers, b end-grafted chains, c triblock copolymers, d multiply grafted chain, and e random copolymer...

Fig. 13. Schematic of a triblock copolymer at the interface between PS and PVP showing the staple or the tail structure contributing respectively two and one connector per chain...

Fig. 39. Schematic of the conformation of block copolymers inside lamellae a diblocks and b triblocks. The bridging effect of triblock copolymers is responsible for their better mechanical reinforcement at high copolymer coverage...

Fig. 23 Schematic drawing of site-selective complexation of PPO-PEO-PPO triblock-copolymer by a-CD...

Fig. 6 a-c The synthesis of PEO-PHB-PEO triblock copolymer a, and the schematic illustrations of the proposed structures of a-CD-PEO-PHB-PEO inclusion complex b, and a-CD-PEO-PHB-PEO supramolecular hydrogel c [71]... 

Fig. 10 A Chemical structure of PBLG-PHF-PBLG triblock copolymers B AFM image of a thin film of 1 cast from TFA/CHCI3 (30/70 v/v) C Schematic representation of the spherical nanostructures that can be observed in B D,E AFM images of triblock copolymers 1 (D) and 2 (E) cast from TFA/CHCI3 (3/97 v/v) F Model proposed for the self-assembly of 1 and 2 in the fibrillar structures shown in D and E. (Reprinted with permission from [76]. Copyright 2004. American Chemical Society)...

Fig. 13 Panel for triblock copolymer PEG-PAsp(MPA)-PLL system, a Chemical structure of PEG-PAsp(MPA)-PLL. b Schematic illustration hypothesizing a three-layered micelle formed from the triblock copolymer and pDNA with spatially regulated structure, c In vitro transfection of the luciferase gene to HeLa cells by the micelles from di- or triblock copolymers and polyplex with PEI. The micelles were prepared at a Lys/nucleotide ratio of 2. HeLa cells were incubated with each micelle in a mediiun containing 10% serinn for 24 h, followed by additional 24 h incnbation withont micelles, d The effects of HCQ and NR on the transfection efficiency of the micelles and polyplex. The PEI polyplex was prepared at a N/P ratio of 10. (Fig. 13d Reprinted with permission from [116])...

Fig. 16 a-d Schematic representation of polymer nanoreactors, a Cross section of triblock copolymer vesicle, b Polymersome with encapsulated enzyme and membrane-embedded channel protein. In the case described in the text, the substrate entering the vesicle is ampicillin, and the product of the hydrolysis is ampicillinoic acid, c Polymersome with embedded ionophores allowing Ca2+ ions to enter the vesicle ere they react with phosphate ions to form calcium phosphate crystals, d The LamB protein serves as a receptor to the 1 phage virus which can inject its DNA through the channel into the polymersome [259]. Reproduced with permission of The Royal Society of Chemistry... 

Fig. 17 Schematic representation of ion-channel controlled precipitation of calcium phosphate in block copolymer vesicles (middle drawing), and TEM micrographs right drawing) of phosphate-loaded PMOXA-PDMS-PMOXA triblock copolymer giant vesicles after 1 and 24 h of incubation with CaCl2 solution in the presence of the ionophore scale bar. 500 nm [163]. Reproduced with permission of The Royal Society of Chemistry...

Fig. 22.4 Schematic of the domain organization of the block copolymer chains and the tackifying resin in the blend. Both triblock copolymers and diblock copolymers are represented.

FIGURE 13.8 Schematic illustration of phase separation in a thermoplastic elastomer based on a styrenic triblock copolymer such as SBS. The isolated spherical domains containing the polystyrene end blocks form the hard phase, which acts as both intermolecular tie point ("physical crosslinks ) and filler. The continuous phase from the polybutadiene midblock imparts the elastomeric characteristics to this polymer. 

Schematic figures of the shape memory mechanism of the styrene-butadiene-styrene (SBS) triblock copolymer/poly(e-caprolactone) (PCL) blend in (a)-(d). (Adapted from Zhang, H., Wang, H., Zhong, W, and Du, Q. 2009. A novel type of shape memory polymer blend and the shape memory mechanism. Polymer 50 1596-1601. Copyright Elsevier Ltd. Reproduced with permission.)...

Figure 11 Schematic synthesis of (a) poly (a-hydroxy esters) and (b) triblock copolymers. From D Antone, S. Bignotti, F. Sartore, L. etal. Polym. Degrad. Stab. 2001, 74,119. ...

Figure 34.21 Schematic representation of the A, B, and C building blocks used by Week and co-workers, and the molecular structure of the supramolecular ABC triblock copolymer obtained via one-pot self-assembly. (Reprinted with permission from Ref [81] 2009, Wiley-VCH.)...

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