Molecular Weight Dependence on the Disintegration of Spin-Assisted Weak Polyelectrolyte Multilayer Films

Abstract

We present the effect of molecular weight (MW) of polyelectrolytes (PEs) on the disintegration behavior of weak PE multilayer films consisting of linear poly(ethylene imine) (LPEI) and poly(methacrylic acid) (PMAA). The multilayer films prepared by the spin-assisted layer-by-layer deposition have well-ordered internal structures and also show the linear thickness growth behavior regardless of MWs of PMAA. The well-defined weak PE multilayer films were subject to disintegration into bulk solution when the electrostatic interactions between LPEI and PMAA layers were reduced by treatment at pH 2. However, we demonstrated the change in the disintegration mode and kinetics (i.e., from burst erosion to controlled surface erosion) as a function of MW of PMAA based on neutron reflectivity and quartz crystal microbalance with dissipation, revealing the correlation between the structural changes and the viscoelastic responses of the weak PE films upon pH treatment. Also, the unique swelling behavior as well as the significant increase in dissipation energy was monitored before the complete disintegration of the multilayer films containing high MW PMAA, which is believed to originate from their slow rearrangement kinetics within the film. We believe that the results shown in this study provide chain-level understanding as to the MW-dependence on pH-triggered disintegration mechanism of weak PE multilayer films.

Tuning assembly and enzymatic degradation of silk/poly(N-vinylcaprolactam) multilayers via molecular weight and hydrophobicity

“…For both film types, the pH and enzymatic stability was improved with increasing PVCL length and β-sheet content, indicating enhanced hydrophobic and hydrogen-bonded interactions between PVCL and silk. 32,46,57,58 In our case, the increase in multilayer thickness alongside molecular weight in dipped films correlates well with the increase in PVCL radius of gyration in solution, R g . Our approach gives a unique opportunity to tune thickness, morphology, structure, and biodegradability rate of silk films and capsules by varying silk secondary structure and PVCL length.…”

“…32,46,57,58 In our case, the increase in multilayer thickness alongside molecular weight in dipped films correlates well with the increase in PVCL radius of gyration in solution, R g . Film thickness, surface morphology, wettability, and pH-stability are strongly controlled by deposition conditions and PVCL molecular weight.…”

Influence of poly‐l‐lysine molecular weight on antibacterial efficacy in polymer multilayer films

“…Film swelling, ion exchange, mobility of film components, 89,90 and potential interactions with proteins and cells could result in gradual destabilization of the films; 91 and the rate of dissolution has been shown to be influenced by polyelectrolyte MW. 92 Studies have shown that PLL/HA films formulated with 40-60 kDa PLL and 64 kDa HA dissolved in~16 days in 1× PBS, 93 while PLL/HA multilayers built with 30 kDa PLL but higher MW HA (400 kDa) were stable in sodium chloride solution for several months and for at least 2 weeks in contact with cells and culture media. 94 For PLL 30 and PLL 90 films, the number of effective uses correlated with film stability in media ( Fig.…”

Tuning cell adhesive properties via layer-by-layer assembly of chitosan and alginate

“…[2, 11–13] The overall properties of the film can be controlled simply by adjusting processing parameters: nature of polyelectrolytes, functional groups, molecular weight, charge density, concentration of the adsorption species, adsorption and rising time, pH, ionic strength, and humidity. [14–19]…”