Self-organization method copolymers

So far, the enormous potential of the diblock copolymer approach has been demonstrated which is based on three particular contributions (i) self-organization of block copolymers with periodicities down to a few ten nanometers, (ii) easy application of structurally well controlled thin films over large areas of various substrates, and (iii) the highly selective etching contrast which can be achieved by the incorporation of suitable inorganic components. Most importantly, the latter will allow to prepare nanostructures in semiconductors with an aspect ratio not yet conceivable by other parallel processing methods. 

Munk, P. (1996) Classical methods for the study of block copolymer micelles. In S.E. Webber, P. Munk and Z. Tuzar (eds), Solvents and Self-Organization of Polymer, NATOASI Series, Serie E Applied Sciences Vol. 327. Kluwer Academic Publisher, Dordrecht, pp. 367-381. 

Since then, the research has dramatically grown and many goals have been achieved. A review reports an organized and detailed overview on theoretical aspects and basic principles of self-assembly and micellization of block copolymers in solution, together with a wide number of examples concerning the methods for the stabilization of macromolecular aggregates and their applications, mainly focused on biomedical field, in the perspective of smart nano-objects production [37]. The self-organization of block copolymers in different shapes is depicted in Fig. 1.4. 

According to the solubility of the core-forming monomer in the reaction media, two different methods—emulsion polymerization and dispersion polymerization— have been exploited to obtain self-assembled nanoparticles by PISA [37, 38]. The dispersion polymerization can be carried out either in water or in organic solvents. The emulsion polymerization starts from a monomer-in-water emulsion, where a water-soluble polymer precursor is chain-extended by polymerizing a water-immiscible monomer, resulting in self-assembled block copolymers. In contrast to the emulsion polymerization, dispersion polymerization is conceptually much simpler and the initial reaction solution is homogeneous. 

Concerning nanostructured magnetic nanocomposites, a large part of the research effort in this field is oriented to the control of particle size and organization by self-assembly, block copolymers, dendrimers or liquid crystals. These methods open the possibility of an easy fabrication of nanodevices at mild conditions and they have attracted the interest of the big companies in the field. An illustrative example of research in this field can be found in the work of the magnetic materials group at NIST. ... 

The third method for creating porous materials from self-assembled block copolymers is the use of polymers composed of inorganic materials such as silicon or iron in combination with an easily etched block such as PS, PI, or PMMA. Upon calcination or reactive ion etching of self-assembled films, the organic component of the films is removed and etch-resistant inorganic oxides are formed. Examples of some inorganic-containing etch-resistant bloda include... 

Regarding the third vector, during the last few years there has been significant progress in the synthetic methods that lead to formation of self-organized macromolecular structures, based on the concept of end-groups attractive/repulsive interactions or formation of block copolymers, namely HyperMacs and HyperBlocks. " Control of chain ends also offers means for efficient control of the surface properties, e.g., addition of < 0.5% of multi-functional fluoroalkyl additives transforms PS surface tension to that of PTFE. ... 

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