PEO chains

The successfiil synthesis of a transparent soHd polymer electrolyte (SPE) based on PEO and alkoxysilanes has been reported (41). The material possessed good mechanical properties and high electrical conductivity (around 1.8 x 10 S/cm at 25°C) dependent on the organic—inorganic ratio and PEO chain length. 

The mechanisms of the first- and second-dimension separations are independent here that is, the alkyl chain length separation is independent of the PEO chain length. The retention in this case is often called orthogonal between the two dimensions. A discussion of orthogonal separations is given in Chapters 2, 3, 6, and 12. This independent nature of the two separation dimensions allows the full analysis of the alkyl and PEO components per molecule. Additional examples of the independence in separation axes will further demonstrate the importance of 2DLC for surfactant analysis. 

Sodium 4-oxy-2,2,6,6-tetramethyl-l-piperidinyloxy, TEMPONa, was used as a bifunctional initiator for the synthesis of PEO-fc-PS block copolymers [133]. Initially the ROP of EO was performed in THF at 60 °C to provide narrow molecular weight distribution chains with terminal TEMPO moieties. Using these functionalized PEO chains the polymerization of styrene was... 

Fig.20 Top row single unit-cell models of core-shell double gyroid (Q230), orthorhombic (O70), and alternating gyroid (Q214) cross-sectioned to reveal interfacial configuration. Bottom row. direct projections of cross-sectioned interfaces. Sketches of PI-fi-PS-fi-PEO chains show how each morphology is assembled. Projections appear to scale that is, the core-shell double gyroid unit cell is roughly twice the thickness of the other two. From [75], Copyright 2004 American Chemical Society...

Fig.66 Phase diagrams of a symmetric (peo = 0.51, Mn = 2700, Mw/Mn = 1.10) and b asymmetric (0peo = 0.32, Mn = 2100, Mw/Mn = 1.14) PEO-fc-PEP block copolymers blended with epoxy resin. Phase transitions which originate from swelling of PEO chains with epoxy and/or curing agent are drawn as single lines, without implication that there are no coexistence regions. From [197]. Copyright 2001 Wiley...

The formation of stable nanoparticles has been studied using various derivatives of thermosensitive PNIPAM, including diblock and graft copolymers, PNIPAM-b-PEO and PNIPAM-g-PEO [165-172], In these copolymers, the role of the PEO chains is to solubilise/stabilise collapsed PNIPAM at temperatures above its cloud point. Both the graft and the block copolymers, PNIPAM-g-PEO and PNIPAM-fr-PEO, form spherical core-shell structures in... 

In the second step, amino-terminated PEO chains were finked to the reactive NIPAM copolymers by condensation reaction of the primary amine... 

The solubilising effect of PEO chains was also observed by micro calorimetry. The transition temperatures were 33.5 and 34.3 °C for PNIPAM-g-PEO-6 and PNIPAM-g-PEO-7, respectively. The enthalpy associated with the transition was higher in the case of PNIPAM-g-PEO-6 (2.5 kj mor1 of repeating NI-PAM unit) compared with that of aqueous PNIPAM-g-PEO-7 (1.3 kj mol-1). For both copolymers, it was significantly lower than the enthalpy of the phase transition of linear PNIPAM in water (approximately 7 kj mol-1). 

In this section, we review the properties of a series of PNIPAM-b-PEO copolymers with PEO blocks of varying length, with respect to the PNIPAM block. Key features of their solutions will be compared with those of PNIPAM-g-PEO solutions. PNIPAM-b-PEO copolymers were prepared by free-radical polymerisation of NIPAM initiated by macroazoinitiators having PEO chains linked symmetrically at each end of a 2,2/-azobis(isobutyronitrile) derivative [169,170]. The polydispersities of PEOs were low, enabling calculations of the number-average molar mass for each PNIPAM block from analysis of their H-NMR spectra (Table 2). 

The surface of the PNIPAM-g-PEO and PNIPAM-fo-PEO aggregates is expected to be covered by hydrophilic PEO chains, which impart colloidal stability to the particle. However, some PEO is buried inside the aggregate core. Therefore, increasing mixing of the phases in the core limits core compression. This is especially true in the case of PNIPAM-g-PEO. Whereas the... 

The sizes of charged and neutral particles were measured as a function of increasing temperature (Fig. 18) [178]. The thermal collapse of the PVCL particles turned out to be a more or less continuous process, regardless of particle charge and the presence or absence of amphiphilic grafts. The PEO chains bound to the particle surfaces had only a minor effect on the transition temperature. The sizes of the particles in cold water varied from sample... 

PEO chains have been grafted to this backbone, leading to an amphiphilic copolymer. Aqueous micelles have been then prepared from these copolymers [332]. 

Table 2.1 illustrates the magnitudes of the characteristic ratio found for typical polymers in dilute solution. The relatively simple polyethylene oxide), (PEO), chain is fairly flexible whereas the cellulosic chain has... 

It is difficult to prepare stretched oriented fibres and such fibres may differ in their polymer chain conformation compared with the unstretched materials. Furthermore the quality of the single crystal X-ray data is poor and difficult to interpret. In contrast power X-ray data of relatively high quality may be obtained from polycrystalline polymer films. Lightfoot, Mehta and Bruce (1992) have obtained the first crystal structure of a polymer-salt complex, PEOjiNaClQ from powder X-ray data. Fig. 5.11(h). The structure is similar to the corresponding PEOjiNal structure, the PEO chains are wrapped around the Na ions with each Na ... 

The experiments on alkali iodides, PEOx-Nal or PEOx-Lil [316-318] were performed on PEO chains of 23 or 182 (-CH2-CH2-O-) monomers and Orion ratios between 15 and 50. The incoherent scattering from protonated polymers was measured using INI 1C, which yields the intermediate scattering function of the self-correlation. The experiments were performed in the homogeneous liquid phase where the added salt is completely dissolved and no crystalline aggregates coexist with the solution, i.e. at temperatures around 70 °C. 

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