Characterization of pH-induced changes in the morphology of polyelectrolyte multilayers assembled from poly(allylamine) and low molecular weight poly(acrylic acid)

Sun, Bin; Flessner, Ryan M.; Saurer, Eric M.; Jewell, Christopher M.; Fredin, Nathaniel J.; Lynn, David M.

doi:10.1016/j.jcis.2010.12.019

Cited by 13 publications

(7 citation statements)

References 42 publications

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“…In this regard, the molecular weight (MW) of PE chains could be one of critical and intrinsic control parameters to tune the disintegration behavior of multilayer films without additional post-treatments or the insertion of other strongly binding molecules. It has been reported that the PE MW has a great effect on the surface characteristics and adsorption properties of the multilayer films − as well as on the pH-triggered pore formation of multilayer films. , However, to our knowledge, there are few reports dealing with the disintegration mechanism of multilayer films as a function of MW of PE chains incorporated, especially with quantitative analysis that provides both chain- and thin film structural-level of understanding . In particular, since multilayer films based on weak PEs typically show rapid morphological change and subsequent disintegration when they are subject to low pH treatment, , it is, in general, difficult to investigate the disintegration mechanism in detail when weak PE multilayer films containing short MW PEs start to disintegrate by pH triggering.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2013

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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.

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Section: Introductionmentioning

confidence: 99%

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

et al. 2013

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“…Ion-pairing layer-by-layer (LbL) assembly is a versatile assembly technique based upon the alternate adsorption of oppositely charged polyions onto a surface . LbL films have found widespread applications in drug delivery, − antifouling coatings, , polymer electrolytes, − batteries, ,− solar cells, , optics, and sensors. − The growth and properties of LbL films can be manipulated by varying several external parameters such as assembly solution pH, − ionic strength, , salt type, − and temperature. , …”

Section: Introductionmentioning

confidence: 99%

pH-Dependent Thermal Transitions in Hydrated Layer-by-Layer Assemblies Containing Weak Polyelectrolytes

et al. 2012

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Layer-by-layer (LbL) assemblies have remarkable potential as advanced functional materials with applications in energy and biomedical related areas. However, very little is known about their thermal and viscoelastic properties owing to the inherent difficulty in their accurate measurement. Here we report on the thermal behavior of a model LbL system containing weak polyelectrolytes poly(allylamine hydrochloride) (PAH) and poly(acrylic acid) (PAA) as a function of assembly solution pH. Quartz crystal microbalance with dissipation (QCM-D) and modulated differential scanning calorimetry (DSC) indicate that hydrated PAH/PAA LbL assemblies undergo a thermal transition that is akin to a glass transition for most assembly pH’s investigated, with the exception being the case where both polyelectrolytes are fully charged. The nonmonotonic dependence of the glass transition temperature of the PAH/PAA LbL system with respect to assembly pH is discussed in relation to the film’s hydration, composition, film-growth mechanism (linear vs exponential), and ion-pairing density.

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“…This indicates that there are pores beneath the surface although the film surface is fairly smooth, as shown in Figure 2. This "skin layer" above the pore structure has been observed for linear PEI (LPEI) /PAA LbL films assembled at pH 5 [34] or the PAH/PAA LbL films assembled with low MW PAA [39][40][41]. Its origin remains unclear, but it has been attributed to the higher mobility of the polyelectrolyte in the exponentially grown LbL films.…”

Section: Resultsmentioning

confidence: 92%

“…In another study, a superhydrophobic surface was prepared by the synchronous generation of nano/microscale hierarchical porous structures in the LbL films without nanoparticle deposition using a combination of high-molecular weight (MW) PAH and low-MW PAA with a short deposition time of 1 min [ 36 ]. Recently, porous PAH/PAA LbL films were fabricated using the PAA with a bimodal MW distribution [ 37 , 38 ] based on the fact that the porous structure is influenced by the PAA MW in the PAH/PAA LbL film [ 39 , 40 , 41 ]. It was demonstrated that the surface morphologies and the wetting properties of the porous LbL films could be controlled by adjusting the blend ratio of low- and high-MW PAAs.…”

Section: Introductionmentioning

confidence: 99%

Porous Layer-by-Layer Films Assembled Using Polyelectrolyte Blend to Control Wetting Properties

Sung

Heo

2021

Polymers

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Porous layer-by-layer (LbL) films have been employed for the implementation of superwetting surfaces, but they are limited to the LbL films consisting of only two oppositely charged polyelectrolytes. In this study, LbL films were assembled using a cationic polymer blend of branched poly(ethylene imine) (BPEI) and poly(allylamine hydrochloride) (PAH), and anionic poly(acrylic acid); they were then acid-treated at pH 1.8–2.0 to create a porous structure. The films of 100% BPEI exhibited a relatively smooth surface, whereas those of the 100% PAH exhibited porous surfaces. However, various surface morphologies were obtained when BPEI and PAH were blended. When coated with fluorinated silane, films with 50% and 100% PAH exhibited relatively higher water contact angles (WCAs). In particular, films with 50% PAH exhibited the highest WCA of 140–150° when treated at pH 1.8. These fluorinated films were further infused with lubricant oil to determine their feasibility as slippery surfaces. The water and oil sliding angles were in the range of 10–20° and 5–10°, respectively. Films prepared with the BPEI/PAH blend showed lower water slide angles than those prepared with 100% BPEI or PAH. Acid treatment of LbL films assembled using a polyelectrolyte blend can effectively control surface morphologies and can potentially be applied in superwetting.

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Characterization of pH-induced changes in the morphology of polyelectrolyte multilayers assembled from poly(allylamine) and low molecular weight poly(acrylic acid)

Cited by 13 publications

References 42 publications

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

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

pH-Dependent Thermal Transitions in Hydrated Layer-by-Layer Assemblies Containing Weak Polyelectrolytes

Porous Layer-by-Layer Films Assembled Using Polyelectrolyte Blend to Control Wetting Properties

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