Poly ionic surfaces

Poly(vinyl alcohol) will function as a non-ionic surface active agent and is used in suspension polymerisation as a protective colloid. In many applications it serves as a binder and thickener is addition to an emulsifying agent. The polymer is also employed in adhesives, binders, paper sizing, paper coatings, textile sizing, ceramics, cosmetics and as a steel quenchant. 

In recent years, there has been a steady shift away from the LB technique toward self-assembly methods for the fabrication of mono-layer and multilayer arrays (Fig. 12). In contrast to the LB method, which requires a film balance and careful control over surface pressures during dipping and transfer, self-assembly is carried out by simple immersion of a suitable support into a solution containing an excess of monomer. The formation of multilayer arrays via self-assembly has also become popular. Most commonly, a charged surface is dipped into a solution containing a poly ionic species, followed by dipping into a second solution that contains a polymeric counterion. Repetition of such dipping then produces the desired material in a layer-by-layer manner. 

There has been only one report describing SI-NMP from a metal oxide other than those of titanium and iron, namely from a copper oxide surface [44]. In this study, poly(ionic liquid) was grafted onto micro/nanoscale CuO/Cu surfaces by bimolecular-initiated polymerization with TEMPO nitroxide. For this purpose, the peroxide groups were first introduced onto micro/nanoscale CuO surfaces by reaction of 3-chloropropyltrimethoxysilane (immobilized on the CuO surface) with... 

Scheme 14 Process of poly(ionic liquid) growth at CuO surface...

Jia et al. [125] constructed ionic polymer-coated nanofibrous membranes through grafting poly(ionic hquid) brushes (Scheme 8.12) onto the electrospun Si02 nanofiber surface using atom transfer radical polymerization (ATRP) method. They further demonstrated the potential applications of functionalized membranes as an anion-directed molecular gating system and also a membrane with electroactivity via simple counteranion exchange of the attached poly(ionic hquid) brushes. 

SG sols were synthesized by hydrolysis of tetraethyloxysilane in the presence of polyelectrolyte and surfactant. Poly (vinylsulfonic acid) (PVSA) or poly (styrenesulfonic acid) (PSSA) were used as cation exchangers, Tween-20 or Triton X-100 were used as non- ionic surfactants. Obtained sol was dropped onto the surface of glass slide and dried over night. Template extraction from the composite film was performed in water- ethanol medium. The ion-exchange properties of the films were studied spectrophotometrically using adsorption of cationic dye Rhodamine 6G or Fe(Phen) and potentiometrically by sorption of protons. 

The ready formation of polyanions from poly(acrylic acid) grafts or of polycations from a polyaminated surface leads to a polyvalent anionic or cationic interface. Such interfaces can be modified ionically (as in ionic... 

---