Giant polymers

Polymeric silicones are extensively used in applications which require thermal stability and long-lasting retention of critical properties. They can be produced in various degrees of hardness and resiliency by combining prepolymer fluids, which contain reactive functional groups, in such ways as to form giant polymer networks with those desired properties. 

Zhou, Y.F. and Yan, D.Y. (2005) Real-time membrane fusion of giant polymer vesicles. Journal cf the American Chemical Society, 127 (30), 10468-10469. 

The parameter b does not change with temperature, being a constant value for each polymer. The temperature independence of b in the range of temperature of the data indicates low kinetic energy of the giant polymer molecules. 

Howse JR, Jones AR, Battaglia G, Ducker RE, Leggett GJ, Ryan AJ (2009) Templated formation of giant polymer vesicles with controlled size distributions. Nat Mater 8(6) 507-511... 

In a PHIC chain, the backbone, covered by a corona of hexyl groups, consists of a Unear sequence of imide units. Their counterparts in the PS-PCEMA nanofiber are the cross-linked PCEMA cylindrical core and the PS chains as the corona. Other than the size difference, the PHIC molecule and the PS-PCEMA nanofiber bear a remarkable structural resemblance. If the PCEMA crosslinking density is high, the PtBA chains in a PS-PCEMA-PtBA nanofiber and the PAA chains in a PS-PCEMA-PAA nanotube become trapped inside the cores even if the solvent is good for both PtBA and PAA. Thus, the triblock copolymer nanofibers and nanotubes can be viewed as giant polymer chains as well [18]. 

The polymer network of temperature-sensitive hydrogels is made up of smaller repeating units called monomers. In addition to monomers, the so-called cross-linker groups are present in the polymer network. The cross-linker groups form coimections between different strands of polymer inside the polymer network. As a result a single giant polymer molecule is formed which is incapable of dissolving. 

Hydrogen cyanide is not the only small molecule that is used to manufacmre the molecular giants, polymers. One of the most popular demonstrations in polymer chemistry—the synthesis of slime —uses borax as a cross-linker, a molecule that forms bonds between two polymer chains. Borax and boric acid have many uses, both industrially and in the household. Like HCN, boric acid is an example of a weak acid. 

Similar giant polymer-like assemblies of phosphatidylnucleosides (lib) were also observed in solution by light scattering and small-angel neutron-... 

Polymers with a branching structure and composed of a great many monomers can thereby be generated. When the fraction p of NCO groups having reacted with an OH group exceeds the threshold Pc, there exists a giant polymer whose size is only limited by the dimensions of the reaction bath, i.e., the reaction vessel. 

In polymers, the monomers are covalently linked to each other. If each monomer is connected to two others, a linear chain is obtained. In some polymers, a fraction of the monomeric units share a bond with three (or more) other monomers. In those cases, branched chains are developed, which usually lead to giant polymer molecules. This may even result in a molecular network in which solvent is entrapped. Such a network is referred to as a polymer gel. Figure 12.1 shows these differently structured polymer molecules. In this chapter, we will focus mainly on linear polymers. In Section 12.8, attention is paid to polymer gels. 

Gelation is a critical phenomenon of connectivity and as such we will use the percolation theory to describe it. As percolation theory was described in detail, here we recall the behaviors of measurable quantities which experimental results are given hereafter. Below the gelation threshold the system is composed of finite size polymers branched in the 3-dimensions of space. We shall call those polymers "polymers clusters" in order to distinguish them from other branched polymers as stars or combed polymers. Below the gelation threshold, the system is viscous at zero frequency. At the gelation threshold, there appears a giant polymer clus-... 

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