Spin-Assembled Layer-by-Layer Films of Weakly Charged Polyelectrolyte Multilayer

Abstract

We investigate the effect of film deposition methods on the film properties of layer-by-layer assembled polyelectrolyte multilayers. Multilayered structures of linear polyethylenimine (LPEI) and poly(acrylic acid) (PAA) are prepared by using conventional dipping-based assembly as well as spin-assisted assembly. While the polyelectrolyte interpenetration by the diffusion motion of LPEI species is allowed in dipping-based assembly, an instantaneously and kinetically frozen phase of the film deposition is obtainable from spin-assisted assembly. Being kept from the interdiffusion of LPEI, a stratified internal structure is expected in the spin-assisted assembly, which is completely contrasted to the intermixed phase in the dipping-based assembly. The ability to control the inner structure of the multilayered film enables us to manipulate the physical properties or chemical activity of the functionalized thin films. We also demonstrate that the control over the strength of polyelectrolyte interdiffusion on a very top surface can be utilized for a quantitative manipulation on the degree of macromolecular self-assembly of nanomaterials.

Layer‐by‐layer films based on catechol‐modified polysaccharides produced by dip‐ and spin‐coating onto different substrates

“…Figure showed that the spin‐coating process contributed to LbL films with more uniform and ordered coating structures compared to those obtained by dip‐coating, using glass as the substrate. This finding was in agreement with some previous observations (Cho et al, ; Lee et al, ). Cho et al () prepared spin‐ and dip‐coated poly(allylamine hydrochloride)/poly(sodium 4‐styrenesulfonate) films and the AFM analysis evidenced highly ordered structures for the spin‐coated ones.…”

“…Moreover, it was believed that the centrifugation step in the spin‐coating method, or the interlayer diffusion of polyelectrolytes in the dip‐coating method, gave rise to the presence of polymeric agglomerations of the coating components that were not completely removed (Marudova et al, ). In fact, dip‐coated films have demonstrated to present more polyelectrolyte interpenetration between the layers than spin‐assisted films contributing to an exponential growth of film thickness and less ordered structures (Cho, Char, Hong, & Lee, ; Lee et al, ; Marudova et al, ). In addition, the exponential growth is usually observed for weakly charged PEM systems and can be attributed to the reversible interdiffusion of at least one of the polyelectrolyte species that constitute the film (Marudova et al, ).…”

“…Cho et al () prepared spin‐ and dip‐coated poly(allylamine hydrochloride)/poly(sodium 4‐styrenesulfonate) films and the AFM analysis evidenced highly ordered structures for the spin‐coated ones. Lee et al () developed spin‐ and dip‐coated linear polyethylenimine/poly(acrylic acid) films and, based on the investigations of the surface roughness and the relative composition of constituting polyelectrolytes, concluded that spin‐coating films showed less polyelectrolytes interpenetration between the layers, producing a linear growth of the thickness, rather than the common exponential growth in the LbL assembly by dip‐coating.…”

Increase in Interfacial Adhesion and Electrochemical Charge Storage Capacity of Polypyrrole on Au Electrodes Using Polyethyleneimine

“…O 2 plasma treatment (Plasma Cleaner, PDG-32G, Harrick Plasma) was performed for 2 min on the Au electrode. For PEI (MW = 750,000 g mol −1 , Sigma Aldrich) adsorption, the electrode was immersed in a 0.5 mg/mL PEI solution for 24 h. For the preparation of thick polymer-coated Au electrodes, a plasma-treated Au electrode was coated with a layer-by-layer assembly of a positively charged polymer (linear polyethyleneimine, LPEI) and a negatively charged polymer (poly(acrylic acid), PAA (MW = 250,000 g mol −1 ) 9 . The layer by layer assembly process is shown in Fig.…”

“…To address the delamination issue, we have developed a new strategy that utilizes an adhesion-enhancing layer between the CP layer and the metal electrode. Herein, we examined a high-molecular-weight branched polyethyleneimine (PEI) as a candidate material for such an adhesion-enhancing layer because of its good adhesion to metals 8 , charged polyelectrolytes 9 , and cells 10 via van der Waals or ionic/polar group interactions. Moreover, its chain flexibility and large free volume are suitable for accommodating an incipient electropolymerized CP layer.…”