Odd‐even effect during layer‐by‐layer assembly of polyelectrolytes inspired by marine mussel

Abstract

Biomimetic polyelectrolyte of Dopa modified poly(acrylic acid) (PAADopa) was synthesized taking advantage of Dopa, the major unit of marine adhesive proteins. Zinc crosslinked PAADopa (PAADopa‐Zn) were formed at acidic pH for more compact structure and assembled with the positively charged polyethylenimine (PEI) to build robust polyelectrolyte multilayers at high salt concentration. Effects of pH, crosslinking degree, and salt concentration on polymer structure, film building process, and morphology were investigated, respectively. An “odd‐even” effect was observed by quartz crystal microbalance with dissipation and AFM in the presence of zinc ion, which becomes more obvious with an optimum crosslinking degree (Zn/Dopa = 2.0) under high salt concentration (0.6 M NaCl). It indicates the different swollen properties of PEI chain and PAADopa‐Zn complexes during the layer‐by‐layer building process under optimum crosslinking degree of PAADopa‐Zn at high salt concentration. Such odd‐even phenomenon of the biocompatible system is of critical importance for understanding the mechanism of layer formation and film structures. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017, 55, 245–255

Model Surfaces for Paper Fibers Prepared from Carboxymethyl Cellulose and Polycations

“…The PDADMAC terminated PEM ( Figure 7 a, BL) swells more strongly because of a higher concentration of counter ions [ 43 ] and therefore a higher osmotic pressure in the PEM [ 25 , 44 ]. This dependency of the water uptake on the outermost PE layer is commonly observed for PEMs and known as the odd-even effect [ 32 , 44 , 45 , 46 , 47 ].…”

Multilayer assembly of ionic starches on old corrugated container recycled cellulosic fibers

“…Surface charge inversion after every deposition step is an essential precondition for PEM formation . As shown in Fig.…”

“…The building blocks of PEMs can range from small organic molecules to inorganic compounds and macromolecules including polysaccharides, proteins, viruses, DNA and various kinds of nanoparticles, showing a possible way for surface engineering to achieve desired properties . This ecofriendly technique can be enabled to control film structure and properties to realize successful PEM construction with tunable behaviors . Polyelectrolyte thin film layers obtained by LbL deposition are continuously studied due to their potential applications in various technologies, and interesting fundamental questions arise from their complex nature .…”

Polyelectrolyte Gels: Fundamentals, Fabrication and Applications

“…The favourable adhesive properties exuded by mussels (the most common organism researched for underwater adhesion) have been extensively explored in numerous reviews [ 123 , 124 , 125 ], where 3,4-dihydroxy-phenylalanine (DOPA) moieties are considered the primary source of mussel adhesion in their natural environment. To exploit this property, a DOPA-modified PAA layer crosslinked with zinc was incorporated as the polyanionic component alongside a positively charged PEI layer to determine the effects of LBL assembly of PEs [ 126 ]. The multilayered system was comparative to the bioactive C-CHT system.…”

“…In contrast, a more compact structure was obtained for an adhesive polyanionic layer dominated by a more crosslinked structure, preventing the absorption of the surrounding liquid environment. Thus, an odd-numbered multilayer presents a more hydrophilic nature with a loosely packed structure, thereby negatively impacting the overall parameters such as thickness, swelling and adhesion [ 126 ]. DOPA moieties have further shown their advantages in obtaining excellent underwater adhesion, where Jiao et al [ 95 ] demonstrated how their polyelectrolytic system could withstand ~200 min of ultrasonication with only a negligible change.…”