Poly(styrene sulfonate) self‐organization: electrostatic and secondary interactions

Abstract

We investigate the self‐organization of PSS in brushes and polyelectrolyte multilayers with X‐ray, neutron and optical reflectivity. The electrostatic force dominates brush phases and adsorption behavior, additionally we find evidence of a strong hydrophobic force: (ι) within amphiphilic diblock copolymer monolayers, a PSS monolayer adsorbs flatly to the hydrophobic block, (ιι) on temperature increase (and with screened electrostatic forces), more PSS is adsorbed onto oppositely charged surfaces, and (ιιι) a polyelectrolyte multilayers shrinks when heated at 100% r.h. The latter two effects are consistent with the well‐known increase of the hydrophobic force on heating: The increased PSS surface coverage can be attributed to deteriorating solvent conditions. Within a polyelectrolyte multilayer, an increase of the hydrophobic force maximizes the local contact of hydrophobic polymer segments, causing a reduction of swelling and an increased mass density.

Multifaceted pH and Temperature Induced Self‐Assembly of P(DMAEMA‐co‐LMA)‐b‐POEGMA Terpolymers and Their Cationic Analogues in Aqueous Media

“…In cases like this, the response to pH changes is affected by the molecular weight (as in the case of PDMAEMA homopolymer), the concentration in aqueous solutions, the composition, the architecture of the copolymer, and the hydrophobic segments, if present, in the copolymer. [ 26,40 ] This also applies in the present polymeric systems, as DMAEMA is a component of the macromolecular chains.…”

“…In the case of aqueous solutions of polyelectrolytes with hydrophobic segments, heating the solution results in the enhancement of the hydrophobic forces developed between the hydrophobic groups, which induce growth of the mass density and decrease of the nanostructure “swelling” by water. [ 40 ] Hydrophobic moieties are not able of forming hydrogen bonds with water molecules, and as a result, they are pulled together and eventually aggregate into hydrophobic domains while excluding water molecules. As temperature increases, the ability of water molecules to move around the hydrophobic units results in their further aggregation due to the rise of the hydrophobic interactions.…”

Effects of Hydrophobic Modifications on the Solution Self-Assembly of P(DMAEMA-co-QDMAEMA)-b-POEGMA Random Diblock Copolymers

“…The nanostructures formed from the self-assembly of the random diblock copolymers that contain alkyl chains of twelve carbon atoms are anticipitated to present more hydrophobic character. This hypothesis is based on the existence of longer hydrophobic chains and thus amplification of hydrophobic interactions that will result to lower interaction with water molecules [ 61 ]. Furthermore, the coexistence of DMAEMA units along with QDMAEMA residues will affect the response of DMAEMA units to pH and temperature changes.…”

“…In case of temperature increase, the phase transition from a hydrated/hydrophilic state to dehydrated/more hydrophobic state is expected to occur at lower temperature values than the reported LCST of the PDMAEMA homopolymer. This particular behavior is assigned to the presence of entirely hydrophobic molecules that will assist to the dehydration of the polymeric system due to amplification of the hydrophobic interactions [ 61 ]. Light scattering techniques were utilized to examine the self-assembly of the modified diblock copolymers in aqueous solutions as a response to pH and temperature changes.…”

Defect formation in thin polyelectrolyte films on polycrystalline NiTi substrates

“…adsorbed on planar interfaces as coating (Decher, 1997;Hammond, 2004), adsorbed on particles , as free-standing membranes (Krasemann and Tieke, 2000) or as membranes of capsules Sukhorukov et al, 2000). Multilayer assemblies were constructed on the basis of electrostatic force, also secondary interactions, such as hydrogen bonding (Stockton and Rubner, 1997;Sukhishvili and Granick, 2002;Wang et al, 1997), hydrophobic interactions (Ahrens et al, 2004;Cochin and Laschewsky, 1999;Guyomard et al, 2005) and charge-transfer complexation (Shimazaki et al, 1997;Shimazaki and Ito, 2000) can act as the driving force. By modifying external parameters such as adsorption time, ionic strength (Antipov et al, 2003;Dubas and Schlenoff, 2001;Fery et al, 2001), pH (Mendelsohn et al, 2000;Shiratori and Rubner, 2000), temperature (Köhler et al, 2004(Köhler et al, , 2005, the thickness, morphology and the related properties of the polyelectrolyte films can be adjusted over a broad range.…”