Hydrogen-Bonded Multilayers of Poly(carboxybetaine)s

Abstract

Using a layer-by-layer (LbL) sequential adsorption technique, we studied the construction of hydrogen-bonded multilayers of a weak polycarboxybetaine (poly-N-ω-carboxypentyl-4-vinylpyridinium bromide (PCB5)) with poly(N-vinylcaprolactam) (PVCL). Self-assembly occurred at low pH values where carboxylic groups of PCB5 units were protonated and capable of binding with hydrogen-accepting groups of PVCL. Multilayers could not be constructed, however, in 0.01 M buffer solutions at pH 2.5, and potassium halide salts were required to promote multilayer deposition. Concentrations of halide salts at which deposition of PCB5/ PVCL multilayers occurred decreased in the series KCl > KBr > KI, following the Hofmeister series for binding of anions with PCB5 chains. Using a N-vinylcaprolactam copolymer which contained amino groups (PVCL-NH 2 ), PCB5/PVCL-NH 2 multilayers were constructed and covalently cross-linked, producing surface-attached hydrogels. The hydrogels showed typical polyelectrolyte salt-induced contraction at pH 2.5, where PCB5 units were cationic, but "antipolyelectrolyte" behavior, i.e., swelling in salt solutions at pH 7.5, where PCB5 units were zwitterionic. PCB5/PVCL-NH 2 surface hydrogels were resistant to adsorption of negatively charged proteins and heparin at pH 7.4 in 0.15 M NaCl solutions. The produced PCB5/PVCL films and cross-linked PCB5/ PVCL-NH 2 surface hydrogels might find applications as erasable films or as zwitterion-containing bioinert coatings, respectively.

Fabrication of free-standing polyelectrolyte multilayer films: A method using polysulfobetaine-containing films as sacrificial layers

“…The (PDDA/P4VPPS) 10 -(PDDA/PSS) 27 multilayer film was then immersed into the alkali solution with pH 12 in order to disintegrate the PDDA/P4VPPS sublayer. Fig.…”

“…7 shows the photographs of a (PDDA/P4VPPS) 10 -(PDDA/PSS) 27 multilayer film on gold-polished At-cut quartz crystal after being immersed in the alkali solution with pH 12 for 0, 10, and 30 min. Taking the immediately immersed (PDDA/P4VPPS) 10 -(PDDA/PSS) 27 film as a reference (Fig. 7a), the scratched sides gradually appear by careful stripping after 10 min of immersion, indicating the partial separation of the multilayer film from the substrate (Fig.…”

“…Schlenoff et al prepared LbL multilayer films of poly (2-vinylpyridine propylsulfobetaine) (P2VPPS) with PSS or PAA at low pH (pH < 1) [25]. Kharlampieva et al reported the electrostatic LbL self-assembly of poly(carboxybetaine)s (PCB) with poly(sodium 4-styrenesulfonate) (PSS) and the disintegration of PCB/PSS multilayer films at pH 7.2 [26,27]. The disintegration of pH-dependent LbL multilayer films at various pH conditions makes them potential candidates as the sacrificial layers.…”

Assembly of Nanotubes of Poly(4‐vinylpyridine) and Poly(acrylic acid) through Hydrogen Bonding

“…[26,27] Sukhishvili et al prepared erasable hydrogen-bonded multilayers containing weak polyacids, which could be assembled at low pH values and subsequently dissolved at higher pH values. [28,29] With this feature, one could consider constructing a new type of porous polymer complex film with potential applications in many fields, such as biology and medicine. [28,30] In this study, we used PVP and PAA as hydrogen acceptor and donor, respectively, to prepare multilayer complex nanotubes via a hydrogen-bonded LbL assembly in an organic solvent.…”

“…[28,29] With this feature, one could consider constructing a new type of porous polymer complex film with potential applications in many fields, such as biology and medicine. [28,30] In this study, we used PVP and PAA as hydrogen acceptor and donor, respectively, to prepare multilayer complex nanotubes via a hydrogen-bonded LbL assembly in an organic solvent. The structural changes in these assembled nanotubes were also investigated in a basic aqueous solution.…”