Hydrophilic nanochannels

The general picture is such that the majority of excess protons are located in the central part of the hydrated hydrophilic nanochannels. In this region, the water is bulklike (for not too low degrees of hydration) with local proton transport properties similar to those described for water in Section 3.1.1.1.1. Therefore, the transport properties are indeed a function of the considered length and time scales,22 225 activation enthalpies of both... 

The combination of thermal annealing and crosslinking, which can be done here at 250 °C by the trimerization of the terminal ethynyl groups, results in a morphological transformation. An eventual nanophase separation between the hydrophilic and hydrophobic domains forms well-connected hydrophilic nanochannels. These show a dramatically enhanced proton conduction. 

The two-dimensional (2D) reverse hexagonal (H2) phase consists of water-filled cylindrical rods (hydrophilic nanochannels) embedded in a... 

It is evident that the bicontinuous cubic phases can solubilize significantly more water at ambient temperatures in their hydrophilic nanochannels as compared to those of the H2 and L2 phases that are formed at higher temperatrrres [83]. 

Lee KP, Leese H, Mattia D (2012) Water flow enhancement in hydrophilic nanochannels. Nanoscale 4 2621-2627... 

In perfluorinated sulfonic acid polymers there are relatively few fixed ionic groups. They are located at the end of side chains, so as to position themselves in their preferred orientation to some extent. Therefore, they can create hydrophilic nanochannels, so called cluster networks [Gierke and Hsu [22] and Gierke, Mimn and Wilson [23]]. 

Figure 11.12 shows an example of the measured position of the moving meniscus versus time in capillary filling of hydrophilic nanochannels by deionized (DI) water (thin "native" silicon dioxide channel bottom and borosilicate glass channel roof, rectangular... 

A mesoscale simulation was employed to investigate the phase morphology of the comb-shaped polymer membranes. In the periodic 3D images, all the membranes display well-connected hydrophilic nanochannels, which become thicker and more interconnected as the graft chain length increased. 

Poly(vinyl alcohol) (PVA) substrates coated with a non-porous hydrophilic polymer/multiwalled nanotube (MWNT) nanocomposite layer have been put forward for potential use in oil/water emulsion separation (Wang et al, 2005). Specifically, it has been proposed that CNTs could improve the flux rate for the formation of hydrophilic nanochannels for water transfer through nanocomposite membranes. The immobilization of CNTs in hydrophobic membrane pores was shown to have a favourable effect on water-membrane interactions and to promote higher vapour permeability, since liquid was prevented from entering the membrane pores (Gethard et al, 2011). The literature also mentions improvements in water flux and selectivity when polymeric membranes are loaded with hydrophilic nanofiUers, including silica (Bottino et al, 2001), ZrOj (Bottino et al, 2002) and HO2 (Yang et al, 2006). 

A hydrophilic liquid, water for instance,itself into or through a hydrophilic micro- or nanochannel by capUlary action which is induced by interfacial tensions (Fig. 2a). The capillarity-induced pressure pulling the Uquid along the channel (Fig. 2a and 2b) is expressed by Young-Laplace s equation ... 

The good agreement between calculated and experimental force curves, obtained with Rup as the only adjustable parameter, validates the force calculation method. We find flap values about twice the aperture diameter, which is compatible with a rather hydrophilic tip. The flow in the nanochannel may thus limit the amount of dispensed... 

Ionomer molecules aggregate and phase-segregate into hydrophobic polymer domains and hydrophilic water-filled pathways at the nanometer scale. These phenomena are understood on the basis of scattering data (SANS, SAXS, USAXS). However, the interpretation of such data is still controversial. Structural pictures of the membrane morphology, focusing on sizes, distribution, and connectivity of water-filled nanochannels, are still going through revisions. Relatively well established is... 

---