Polyelectrolytes
"Polyelectrolytes are polymers whose repeating units bear an electrolyte group. These groups will dissociate in aqueous solutions (water), making the polymers charged. Polyelectrolyte properties are thus similar to both electrolytes (salts) and polymers (high molecular weight compounds), and are sometimes called polysalts. Like salts, their solutions are electrically conductive. Like polymers, their solutions are often viscous. Charged molecular chains, commonly present in soft matter systems, play a fundamental role in determining structure, stability and the interactions of various molecular assemblies. Theoretical approachesto describing their statistical properties differ profoundly from those of their electrically neutral counterparts, while their unique properties are being exploited in a wide range of technological and industrial fields. One of their major roles, however, seems to be the one played in biology and biochemistry. Many biological molecules are polyelectrolytes. For instance, polypeptides (thus all proteins) and DNA are polyelectrolytes. Both natural and synthetic polyelectrolytes are used in a variety of industries." (Wikipedia, Polyelectrolytes, 4/23/2011)
Ionomers
Polymers /Resins
Superacids
Supramolecular Polymers
Recent Journal Articles
Unusual collapse of highly hydrated polyelectrolyte multilayers with the ionic strength
(2346–2352)Journal of Polymer Science Part A: Polymer Chemistry 49 #11 (2011)
Ramos, Llarena and Moya, Spain, fabricated highly hydrated polyelectrolyte multilayers (PEMs) by “layer by layer” (LBL) assembly of poly (diallyl dimethyl ammonium chloride) (PDADMAC) and poly (sodium 4-styrene sulfonate) (PSS) in 0.5 M NaCl. The response towards the ionic strength was then studied by means of QCM-D. PEMs of 17 layers, with PDADMAC as last layer, shrunk dramatically and lost water when exposed to aqueous NaCl solutions of increasing concentration. Indeed, a thickness variation up to 100 nm and reduction in the 50% of the water content were observed when the PEM was exposed to 1 M NaCl. On the contrary, PEMs where PSS appears on top showed no measurable change upon the variation in the ionic strength. This brings the possibility to control the responsive character of the PEMs simply by selecting the last polyelectrolyte layer (PDADMAC or PSS) deposited. (RDC 4/22/2011)