Controllable disintegration of temperature-responsive self-assembled multilayer film based on polybetaine

Gui, Zhangliang; Qian, Jinwen; Zhao, Qiang; Ji, Yan-Li; Liu, Yanxing; Liu, Tao; An, Quan‐Fu

doi:10.1016/j.colsurfa.2011.02.049

Cited by 27 publications

(24 citation statements)

References 52 publications

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“…The J‐V curves of DSSCs for 3 and 5 PPy:PSS multilayer films exhibits less squareness and lower FF values of 0.50 and 0.639, respectively, which is lower than Pt CE. This is an indication of higher R ct developed in multilayer films and is in accordance with the EIS values which will depress the electron transport, resulting in poor solar cell performance . Although the DSSCs are fabricated with same FTO glass, TiO 2 films and electrolyte, the different CE will have major influence on different DSSCs impedances.…”

Section: Resultssupporting

confidence: 57%

“…Although the standard DSSC with Pt as the CE has better cell efficiency under the same measurement conditions, the variable elementary defects in the PPy:PSS can trap the electrons and lower the conductivity of the thin film showing relatively lower performance for multilayer films. This may be due to the formation of microporous structures indicating some disintegrable components released from multilayer films . For multilayer PPy:PSS films, more number of PSS incorporated in to the PPy, will induce some unbounded PPy chains which may prevent transferring electrons between bounded PPy chains.…”

Section: Resultsmentioning

confidence: 99%

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Multilayer photoactive nanocolloidal PPy:PSS as a novel substitute for Pt free counter electrode in DSSC

Maruthamuthu

Chandrasekaran

Manoharan

et al. 2015

J of Applied Polymer Sci

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Water dispersible and highly processable, Polypyrrole (PPy) nanocolloidal particles were synthesized by chemical oxidation polymerization with 15 wt % of anionic polyelectrolyte poly(styrene sulfonate) (PSS) at 58C has been reported in this work. This polymer composite (PPy:PSS) was competent with conventional Pt counter electrode (CE) when compared for dye sensitized solar cells (DSSCs). Morphological analysis revealed smooth and spherical shaped nanoparticles of PPy. Interaction between the SO 3 H groups and Py units in PPy improved the thermal stability of PPy with higher doping levels of PSS. The nanocolloidal solution was spin coated at 4000 rpm. The layer by layer, self-assembled multilayer thin films were used as CE in DSSCs. There was a linear dependence of DSSCs performance with film roughness for the self-assembled multilayer PPy:PSS films. Single layer films showed better electrocatalytic behavior than multilayer films. All the PPy:PSS films had good electrochemical stability. The DSSC efficiency of 3.40% was observed for chemically oxidized PPy with 15 wt % PSS for single layer film, with a highest FF of 0.7154. The low cost, good performance, rapid and simple fabrication method of PPy:PSS composite modified CE could be a potential alternative for Pt in the DSSCs.

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Section: Resultssupporting

confidence: 57%

Section: Resultsmentioning

confidence: 99%

Multilayer photoactive nanocolloidal PPy:PSS as a novel substitute for Pt free counter electrode in DSSC

Maruthamuthu

Chandrasekaran

Manoharan

et al. 2015

J of Applied Polymer Sci

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“…), which can be used in the deposition process . Also, the properties of multilayer films are influenced by the assembly conditions, such as the concentration, pH, ionic strength and temperature of deposition solutions . All these parameters allowed the design of a large variety of multilayer films, which have found applications as separation membranes, anticorrosion, and flame‐retardant coatings, antimicrobial membranes, drug delivery systems, etc.…”

Section: Introductionmentioning

confidence: 99%

Sorption/release of diclofenac sodium in/from free‐standing poly(acrylic acid)/poly(ethyleneimine) multilayer films

Ghiorghiță¹,

Bucătariu²,

Drăgan³

2016

J of Applied Polymer Sci

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Polyelectrolyte multilayer films deposited onto various substrates have been used extensively as drug delivery systems. However, little attention has been paid to the release of drugs from free‐standing polymeric films. Herein, we report the construction of thermal crosslinked free‐standing poly(acrylic acid) (PAA)/branched poly(ethyleneimine) (PEI) multilayer films composed of 25 double layers [(PAA/PEI)25] and their use in sorption/release of diclofenac sodium (DS). The (PAA/PEI)25 multilayer films were characterized by scanning electron microscopy, potentiometric titrations and Fourier transform infrared spectroscopy, while the sorption/release of DS was monitored by UV–Vis spectroscopy. The DS sorption equilibrium data were fitted with five isotherm models (Langmuir, Freundlich, Sips, Dubinin–Radushkevich, and Temkin). The maximum equilibrium sorption capacity, qm, given by the Langmuir model was 32.42 mg DS/g. The Korsmeyer–Peppas semiempirical equation showed that the release of DS from the free‐standing (PAA/PEI)25 films proceeded by pseudo‐Fickian diffusion, irrespective of the releasing media. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43752.

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“…In addition to these, a few other studies have been reported aerwards. [32][33][34] These studies presented successful incorporation of polybetaines into multilayers. However these lms were either not stable at physiological pH or stable but showed no response at physiologically related pH values.…”

Section: Introductionmentioning

confidence: 96%

pH-responsive layer-by-layer films of zwitterionic block copolymer micelles

et al. 2014

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We report a strategy to incorporate micelles of poly[3-dimethyl (methacryloyloxyethyl) ammonium propane sulfonate]-block-poly[2-(diisopropylamino)ethyl methacrylate] (bPDMA-b-PDPA) into electrostatic layer-by-layer (LbL) films. We obtained micelles with pH-responsive PDPA-cores and zwitterionic bPDMA-coronae at pH 8.5 through pH-induced self-assembly of bPDMA-b-PDPA in aqueous solution. To incorporate bPDMA-b-PDPA micelles into LbL films, we first obtained a net electrical charge on bPDMA-coronae. Negative charges of the zwitterionic units were screened through complexation of bPDMA-b-PDPA micelles and poly(allylamine hydrochloride) (PAH). Positively charged micellar complexes were then self-assembled at the surface using poly(sodium 4-styrenesulfonate) (PSS). The pH-stability of the multilayers was examined by exposing the films to decreasing pH values. Despite the disintegration of micellar complexes below pH 7, no change in film thickness was recorded between pH 8.5 and 3.5. Only $20% of the film released at pH < 3.5. Moreover, we demonstrated that when multilayers were exposed to decreasing pH at a temperature below the upper critical solution temperature (UCST) of betainized coronal chains, the film thickness increased by 20% between pH 4.5 and 3. This is probably due to phase separation of the corona block and formation of voids within the film, probably entrapping water molecules within the multilayers. Decreasing temperature also shifted the critical disintegration pH (onset of multilayer dissolution) to a slightly lower pH. By taking advantage of the pH-responsive cores, we showed that multilayers were capable of releasing functional molecules under moderately acidic conditions. Important biological properties of polybetaines, higher loading capacity of zwitterionic block copolymer micelles than linear polybetaines and pH-response of the multilayers at physiologically related pH values make such films promising for biomedical applications.

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Controllable disintegration of temperature-responsive self-assembled multilayer film based on polybetaine

Cited by 27 publications

References 52 publications

Multilayer photoactive nanocolloidal PPy:PSS as a novel substitute for Pt free counter electrode in DSSC

Multilayer photoactive nanocolloidal PPy:PSS as a novel substitute for Pt free counter electrode in DSSC

Sorption/release of diclofenac sodium in/from free‐standing poly(acrylic acid)/poly(ethyleneimine) multilayer films

pH-responsive layer-by-layer films of zwitterionic block copolymer micelles

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