Microphase-separated block copolyme

A variety of morphologies and properties can be achieved with microphase-separated block copolymers. Copolymers of hard and soft polymer segments have... 

Methyl-l,10-undecadiene, ADMET polymerization of, 442 Michaelis-Menten enzymatic kinetics, 84 Microbial hydrolysis, 43 Microcellular elastomers, 204-205 Microphase-separated block copolymers, 6-7... 

Microphase separated block copolymer systems derived from a high temperature polymer with a thermally unstable polymer that undergoes thermal decomposition at elevated temperature to leave pores In the Insulating layer. 

Fig. 7. Approach to the preparation of polyimide nanofoam using microphase separated block copolymers...

Figure 6.7 Illustration of multipoint hydrogen bonding based self-assembly (a) hydrogen bond formation between barbituric acid functionalized gold nanoparticles and Hamilton receptor functionalized block copolymers and (b) selective deposition of nanoparticles on a microphase-separated block copolymer film. Reprinted with permission fi om Binder et al. (2005). Copyright 2005 American Chemical Society.

Binder WH, Kluger C, Straif CJ, Eriedbacher G. Directed nanoparticle binding onto microphase-separated block copolymer thin films. Macromolecules 2005 38 9405-9410. 

Microphase Separated Block Copolymers with a Solid Matrix. . 79... 

In liquid crystals or LC-glasses one looks for orientational order and an absence of three-dimensional, long-range, positional order. In liquid crystals, large scale molecular motion is possible. In LC-glasses the molecules are fixed in position. The orientational order can be molecular or supermolecular. If the order rests with a supermolecular structure, as in soap micelles and certain microphase separated block copolymers, the molecular motion and geometry have only an indirect influence on the overall structure of the material. 

As we have seen, the phase behaviour of block copolymers consisting of flexible polymer coils is remarkably rich. If one of the blocks is rigid, the copolymer would be expected to exhibit even more complex phase behaviour. For example, the rigid block could be mesogenic. This leads to the possibility of self-assembly of structures consisting of domains of liquid crystalline material within a microphase-separated block copolymer superstructure. Diblock copo-... 

The introduction of perfluorinated groups generally favors microphase separation due to the immiscibility of fluorocarbons with hydrocarbons [66]. Norbornene derivatives with perfluorinated endgroups in the side chain were prepared by Wewerka et al. [67]. Monomer XII contained a relatively long (CF2)8-chain, separated via a long spacer (11 methylene-groups) from the norbornene, whereas monomer XIII has two relatively short (CH2)2(CF2)4-side chains (Fig. 11). Homopolymers and block copolymers were synthesized with one fluorinated monomer (XII or XIII) and one non-fluorinated non-liquid crystalline monomer (NBDE or COEN) with the Schrock-type initiators 4 and 5, respectively, leading to microphase-separated block copolymers. Table 9 and Table 10 summarize the physico-chemical properties of the homopolymers and block copolymers. 

In contrast to that, the short fluorinated side groups of poly-XIII did not lead to thermotropic LC phases, but resulted in microphase-separated block copolymers caused by the hydrophobic and oleophobic character of fluorinated polymers. This interpretation was supported by DSC data, which gave the thermal transitions for both blocks. 

The aligned microphase-separated block copolymer poly-XXVII-h-BA (Sect. 2.3) shows reversible contraction in one dimension - in other words, it acts like an actuator. 

Some of the most important data analysis tools are shown for an image of a microphase separated block copolymer film. The tapping mode AFM height data were subjected to a first order planefit to eliminate the effect of sample tilt (Fig. 2.38). 

Scheme 1 Different possible donor-acceptor active layer morphologies in OPV devices. The left drawing depicts a macrophase separated polymer blend morphology with undefined domains. In the middle and at the right, schematic active layer morphologies of disordered and vertically aligned microphase separated block copolymer thin films are shown. Dark and light grey domains correspond to the donor and the acceptor phase, respectively...

Komura M, lyoda T. 2007. AFM cross sectional imaging of perpendicularly oriented nanocylinder structures of microphase separated block copolymer films by crystal like cleavage. Macromolecules 40 4106 4108. 

Beyond a characteristic temperature Todt [14,20], diblock copolymers self-assemble into microphase-separated morphologies. The theoretically predicted equilibriiun states of such ordered phases correspond to perfect superlattices with various symmetries depending on the volume ratio of both blocks. In particular, lamellar (synunetric diblocks), cylindrical (asymmetric diblocks), and spherical (strongly asynunetric diblocks) morphologies are expected and have been observed [2], For typical copolymers, the characteristic length scale of these microphases is in the range from about lOnm up to some 100 nm. It is justified to say that in the bulk, microphase-separated block-copolymers represent ordered nano-structures. 

Figure 6.25. A lamellar microphase-separated block copolymer in the strong segregation limit - the domain size d is very much bigger than the interfacial width w.

Most of the work in the field of polymer crystalhzation in the last decades has been done on long polymer chains like polyethylene, polypropylene, poly(ethylene oxide) or poly(ethylene terephthalate) which form folded-chain crystals with a typical thickness of about 10 nm [1-5]. In all these cases chain folding plays an important role and crystaUization starts from a chemically homogeneous melt. More recently, the confined crystaUization of polymers in small domains of microphase-separated block copolymers has attracted a lot... 

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