Network-forming liquids

Examples of this type of calculation are reported in Ref. 91-94 and 101-102. We present below representative results for a few network-forming liquids that are known to display anomalous thermodynamic and dynamic behavior. 91,92... 

Becker, S. R., Poole, P. H., and Starr, F. W. (2006) Fractional Stokes-Einstein and Debye-Stokes-Einstein Relations in a Network-Forming Liquid, Phys. Rev. Lett. 97, 055901... 

In his original works, Rosenfeld considered hard spheres, soft spheres, Lennard-Jones system, and one-component plasma [52,53]. Thereafter, the excess entropy scaling was applied to many different systems, including core-softened liquids [17,18,51,54,55], liquid metals [56,57], binary mixtures [58,59], ionic liquids [60,61], network-forming liquids [54,60], water [62], chain fluids [63], and bounded potentials [51,64,65]. 

Ribeiro, M.C.C., Wilson, M., and Madden, PA. (1998) The nature of the vibrational modes of the network-forming liquid ZnCl. J. Chem. Phys, 109,9859-9870. 

DSC studies have shown that multifunctional monomers react quickly to form densely crosslinked networks from liquid monomer solutions. However, even a small amount of unreacted monomer can effectively plasticize a crosslinked network, rendering it more pliable. Eor this reason, mechanical analysis was combined with DSC studies to characterize the physical changes occurring in the proposed dimethacrylate system as polymerization proceeds. Static compression tests (Perkin-Elmer, DMA7e) were completed on disks (d = 11.5 mm, t = 1.7) immediately after they were irradiated for varied times. 

A liquid rubber must be more than just a low molecular weight counterpart of a conventional elastomer. Because of molecular weight, functionality, and network-formation requirements, a liquid rubber needs to be considered as a polymeric entity of its own. This point has been shown by an analysis of the network formed upon vulcanization of a liquid rubber (3). This analysis compares and contrasts two classes of liquid rubbers terminally functional and randomly functional prepoly-... 

The square grid network formed between Cd(N03)2 and 2 was shown to catalyze the cyanosilylation of aldehydes [13]. The treatment of benzaldehyde with cyano-trimethylsliane in a CH2C12 suspension of powdered (Cd(2)2(N03)2 n at 40 °C for 24 h resulted in 2-(trimethylsiloxy)phenylacetonitrile in 77% yield. Further, no reaction was observed with powdered Cd(N03)2 or 2 or the supernatant liquid of a CH2C12 suspension of Cd(2)2(N03)2 alone, and also the shape selectivity was observed in catalysis, 2- and 3-tolualdehyde being cyanosilylated in 40 and 19% yields, respectively. These observations indicate that the reaction was promoted heterogeneously by square grid cavities of Cd(2)2(N03)2 . 

The order must then be frozen in before crystallisation occurs, since this would result in the formation of grain boundaries and a reduction in transport or emission efficiency. Device breakdown is also a possibility. The most efficient way to fix the liquid crystalline order is the formation of anisotropic networks by the polymerisation of reactive mesogens in the liquid crystalline state.Anisotropic polymer networks formed from the thermal or photoinitiated polymerisation of polymerisable, so-called photoreactive, liquid crystalline monomers have been used in a wide variety of electrooptic applications, see Chapter This is a more attractive approach than cross-linking... 

Gels are viscoelastic bodies that have interconnected pores of submicrometric dimensions. A gel typically consists of at least two phases, a solid network that entraps a liquid phase. The term gel embraces numerous combinations of substances, which can be classified into the following categories (2) (/) well-ordered lamellar stmctures (2) covalent polymeric networks that are completely disordered (i) polymer networks formed through physical aggregation that are predominandy disordered and (4) particular disordered stmctures. 

Figure 4.5 Viscosity versus inverse temperature for glass-forming liquids, showing behavior classified as strong, typified by open tetrahedral networks, to fragile, typical of ionic and molecular liquids. Here Tg is defined by the criterion that nlT ) = 10 P. For most of the liquids, the viscosities seem to extrapolate to a common value of around 10" P at high temperatures, corresponding to a fundamental molecular vibrational frequency of around 10 sec-i. (Reprinted from J. Non-Cryst. -Solids, 73 1, Angell (1985), with kind permission from Elsevier Science—NL, Sara Burgerhartstraat 25, 1055 KV Amsterdam, The Netherlands.)...

Single-phase gels and jellies can be described as three-dimensional networks formed by adding macromolecules such as proteins, polysaccharides, and synthetic macromolecules to appropriate liquids. In pharmaceutical applications, water and hydroalcoholic solutions are most common. Many polymer gels exhibit reversibility between the gel state and sol, which is the fluid phase containing the dispersed or dissolved macromolecule. However, formation of some polymer gels is irreversible because their chains are covalently bonded. The three-dimensional networks formed in two-phase gels and jellies are formed by... 

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