Fluoroalkyl side chain polymers

The types of polymers that are used as release coatings include silicone networks, silicone containing copolymers, polymers with long alkyl or fluoroalkyl side chains, fluoropolymers, and polyolefins. These polymers have surface energies that are less than the surface energies of commonly used PSAs, an important feature of release materials. 

Furukawa et al. [21] examined a new synthetic method for fluorosilicones with a high content of fluoroalkyl side chains based on the hydrosilylation of fluorinated olefins with PHMS. They introduced perfluoro-octyl groups into silicone polymers in one step without using the cracking process usually used in the conventional method. Employing the same methodology, Furukawa et al. [22] prepared a series of fluorosilicone homopolymers with... 

Studies on polyacrylate and polystyrene containing fluoroalkyl side chains revealed that their behavior and properties are dominated by the side chain length. For instance, remarkably low surface tension was observed for polymers with fluoroalkyl side chains longer than CgFn which indicated the... 

Y. Katano, H. Tomono, T Nakajima, Surface property of polymer films with fluoroalkyl side chains. Macromolecules 27 (8) (1994) 2342-2344. 

Dendrons attached as side chains on linear polymer chains behave different from free dendrimers and dendrons. Block copolymers, poly(3,5-bis(3,5-bis (benzyloxy)benzyloxy)-benzyl methacrylate-random-methacrylic acid)-block-poly(2-perfluorooctylethyl acrylate), possess poly(benzylether) dendrons and perfluorinated alkyl chains in their side chains (Fig. 4) [85], While an LB film of a copolymer with a medium substitution fraction of poly(benzylether) dendron side chain in poly(methacrylic acid) displays flat surface, a copolymer with high fraction of poly(benzylether) dendron side chains produces the zone texture. Dendron rich blocks are hydrophobic and oleophilic but perfluorinated blocks are solvophobic. Therefore, in this case, the solvophobicity-to-solvophilicity balance must be considered. As a result, copolymers with medium fraction of dendron are laid on solid substrate, but dendron blocks of copolymers with high fraction prefer to arrange at air side of air/ water interface and the fluorocarbon blocks are enforced to exist close to water subphase, resulting in the zone texture [86]. These situations of molecular arrangements at air/water interface are kept even after transfer on solid substrate. By contrast, when perfluorooctadecanoic acids are mixed with block copolymers with high dendron fraction, the flat monolayers are visualized as terrace [87], The monolayers are hierarchized into carboxyl, per-fluoroalkyl, and dendron layers, that is, hydrophilic, solvophobic, and oleophilic layers. In this case, perfluorooctadecanoic acids play a role for ordering of block copolymers. 

Recently, more and more studies have started to focus on side chain engineering, and various flexible chains have appeared in conjugated polymers. These side chains can be categorized based on their compositions, namely, alkyl, hybrid, ionic, oligoether, fluoroalkyl, and latently reactive side chains. In this section, we will introduce some representative side chains used in conjugated polymers, and some recent examples in which side chain engineering has been successfully employed to improve device performance will be highlighted. 

All the homopolymers or copolymers that have been obtained show very interesting properties in terms of thermal stabiUty. They generally present rather low TgS and good stability at high temperature and may thus be used over a wide range of temperature. Fmthermore, in the search for new materials for new applications, the obtention of polymers with specific properties is required, and depending on the nature of their main chain (alkyl, fluoroalkyl, aryl, fluoroaryl, aUcyl ether, etc.) and on the nature of their side chains, these hybrid silicones may be directed to exhibit specific properties. 

The relations between the nature of the polymers and the glass transition temperatures have been studied [ 16], as well as their thermal stability [13,14]. The authors have shown that the presence of an aromatic unit in the main chain increases the Tg, as well as the presence of bulky side groups (phenyl, cyanoalkyl, fluoroalkyl). On the contrary, the presence of vinyl or allyl side groups decreases the Tg. 

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