The Experts below are selected from a list of 93 Experts worldwide ranked by ideXlab platform
Wei Tian - One of the best experts on this subject based on the ideXlab platform.
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In vitro degradation and swelling behaviour of rubbery thermoplastic starch in simulated body and simulated saliva fluid and effects of the degradation products on cells
Polymer Degradation and Stability, 2006Co-Authors: Rui Shi, Quanyong Liu, Yanming Han, Dafu Chen, Tao Ding, Wei TianAbstract:Degradation in vitro is of importance in implanted biological industry. This research investigated the swelling and degradation behaviours of glycerol plasticized thermoplastic starch (GTPS) in simulated body fluid (SBF) and simulated saliva fluid (SSF), respectively. The weight loss, swelling degree and linear extensibility as a function of time were measured. Changes in the morphology (SEM), chemical structure (FT-IR), Crystal Property (XRD) and thermogravimetic Property (TG) during degradation were also investigated. Results show that the degradation in SSF was much quicker than that in SBF. About 1 h was needed for the swelling equilibrium in SBF, which was a little quicker than that in SSF. In alkaline solution the swelling speed and the swelling degree were larger than those in neutral and acidic solutions. The degradation in SBF was typical bulk degradation. In SSF the surface and bulk degradation took place synchronously, but the surface degradation played an important role in the first 2 h. Results from FT-IR and XRD suggest that the glycosidic linkages in starch chains were broken and the Crystal structure in GTPS was destructed during degradation. Cytotoxicity test was used to investigate the effects of the short-term extracted dilutions and long-term degradation products on the cells, which illustrates that the degradation products not only had non-toxicity but also accelerated the cells' growth. © 2006 Elsevier Ltd. All rights reserved.
Rui Shi - One of the best experts on this subject based on the ideXlab platform.
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In vitro degradation and swelling behaviour of rubbery thermoplastic starch in simulated body and simulated saliva fluid and effects of the degradation products on cells
Polymer Degradation and Stability, 2006Co-Authors: Rui Shi, Quanyong Liu, Yanming Han, Dafu Chen, Tao Ding, Wei TianAbstract:Degradation in vitro is of importance in implanted biological industry. This research investigated the swelling and degradation behaviours of glycerol plasticized thermoplastic starch (GTPS) in simulated body fluid (SBF) and simulated saliva fluid (SSF), respectively. The weight loss, swelling degree and linear extensibility as a function of time were measured. Changes in the morphology (SEM), chemical structure (FT-IR), Crystal Property (XRD) and thermogravimetic Property (TG) during degradation were also investigated. Results show that the degradation in SSF was much quicker than that in SBF. About 1 h was needed for the swelling equilibrium in SBF, which was a little quicker than that in SSF. In alkaline solution the swelling speed and the swelling degree were larger than those in neutral and acidic solutions. The degradation in SBF was typical bulk degradation. In SSF the surface and bulk degradation took place synchronously, but the surface degradation played an important role in the first 2 h. Results from FT-IR and XRD suggest that the glycosidic linkages in starch chains were broken and the Crystal structure in GTPS was destructed during degradation. Cytotoxicity test was used to investigate the effects of the short-term extracted dilutions and long-term degradation products on the cells, which illustrates that the degradation products not only had non-toxicity but also accelerated the cells' growth. © 2006 Elsevier Ltd. All rights reserved.
Yuki Nagao - One of the best experts on this subject based on the ideXlab platform.
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Proton-Conductivity Enhancement in Polymer Thin Films
Langmuir, 2017Co-Authors: Yuki NagaoAbstract:Highly proton conductive polymers have long attracted the attention of researchers for use in energy conversion, sensors, catalysts, and other applications. From the viewpoint of the scientific history of the creation of highly proton conductive polymers, one fundamental approach is based on the strategy of phase-segregated structures with strong acid groups. This Feature Article presents a new approach to enhancing the proton conductivity of the polymer thin films using an interface that can modify the degrees of freedom for a polymer structure through interaction between the substrate surface and polymers. I introduce suppressed proton conductivity into Nafion thin films and then specifically examine the enhancement in proton conductivity by the molecular orientation of the polymers. As the last topic, a highly proton conductive organized polyimide thin film is demonstrated using the lyotropic liquid-Crystal Property. Both molecular ordering and the in-plane oriented structure can enhance proton conductivity. Moreover, the optical domain and degree of molecular ordering derived from the molecular weight can contribute strongly to the proton transport Property. ■ INTRODUCTION Proton transfer in ionic channels of biological proteins has attracted the effort of many researchers since the 1960s. 1 Many have investigated the purple membrane including bacterio-rhodopsin to elucidate its fundamental role in proton transport in biological systems. 2−5 Surface proton conduction at the lipid monolayer, including the phenomena of the proton diffusion enhancement at the interface, has also been studied intensively. 6,7 Work in inorganic research fields indicates that diffusion at the interface or grain boundary plays an important role in the ionic conduction. Liang reported in 1973 an approximately 50-fold enhancement in Li + ion conduction using the nonconductive interface of Al 2 O 3 . 8 The sample was simply mixed with inert Al 2 O 3 ultrafine particles in LiI. In most cases, the ionic conductivity enhancement was observed with nonconductive materials such as SiO 2 or Al 2 O 3 as the second phase, which is nearly insoluble in the host material. To elucidate the enhancement phenomena of ionic conductivities at the interface, widely diverse 2D ion conducting materials have been reported from studies conducted over more than 30 years. 9−15 In 2000, Sata et al. demonstrated that ionic conductivity in solid electrolytes can be improved by introducing interfaces that redistribute ions in space-charge regions. 10 These findings gave us the opportunity to improve ionic transport properties using an interface. In recent years, various thin materials have been reported for high proton conduction using the interface concept: multilayer thin films by a layer-by-layer, 16−18 2D-confined Langmuir−Blodgett thin films, 19,20 metal−organic framework thin films, 21 and graphene-based thin films. 22,23 Today, the proton transport Property modulated by the interface attracts researchers of various research backgrounds. Many proton conductive polymers have been reported and intensively studied. 24,25 These designs are based on the phase segregation between the hydrophobic and hydrophilic parts with water uptake. Protons are considered to be transported through the hydrophilic parts. In recent polymer research fields, taking advantage of the interface extends the molecular design such as the oriented structure and organized structure for the highly proton conductive materials. In this Feature Article, I proposed the concept of molecular orientation to improve proton conductivity for various proton conductive polymers using the interface of substrate surfaces. 26−33 The interface can modify the degrees of freedom for polymer structures through interaction with functional groups, wettability, and the surface charge between the substrate surface and polymers. Some proton conductive polymers exhibit an oriented structure by the fabrication of thin films. Their oriented thin films show unique proton transport properties compared to those of nonoriented samples. Some polymer thin films exhibited not only higher proton conduction but also a thickness dependence or substrate dependence for the proton transport Property. Understanding the relation between the structure and proton transport Property is fundamentally important, but this attempt has often been hampered in many highly proton conductive polymers because of less structural information derived from their amorphous or amorphous-like nature. Recent studies by me and co-workers have demonstrated the organized polyimide structure using the lyotropic liquid Crystal Property in the thin films. 30−33 This organized thin film shows a lamellar structure and exhibits in-plane high proton conductivity of more than
Dafu Chen - One of the best experts on this subject based on the ideXlab platform.
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In vitro degradation and swelling behaviour of rubbery thermoplastic starch in simulated body and simulated saliva fluid and effects of the degradation products on cells
Polymer Degradation and Stability, 2006Co-Authors: Rui Shi, Quanyong Liu, Yanming Han, Dafu Chen, Tao Ding, Wei TianAbstract:Degradation in vitro is of importance in implanted biological industry. This research investigated the swelling and degradation behaviours of glycerol plasticized thermoplastic starch (GTPS) in simulated body fluid (SBF) and simulated saliva fluid (SSF), respectively. The weight loss, swelling degree and linear extensibility as a function of time were measured. Changes in the morphology (SEM), chemical structure (FT-IR), Crystal Property (XRD) and thermogravimetic Property (TG) during degradation were also investigated. Results show that the degradation in SSF was much quicker than that in SBF. About 1 h was needed for the swelling equilibrium in SBF, which was a little quicker than that in SSF. In alkaline solution the swelling speed and the swelling degree were larger than those in neutral and acidic solutions. The degradation in SBF was typical bulk degradation. In SSF the surface and bulk degradation took place synchronously, but the surface degradation played an important role in the first 2 h. Results from FT-IR and XRD suggest that the glycosidic linkages in starch chains were broken and the Crystal structure in GTPS was destructed during degradation. Cytotoxicity test was used to investigate the effects of the short-term extracted dilutions and long-term degradation products on the cells, which illustrates that the degradation products not only had non-toxicity but also accelerated the cells' growth. © 2006 Elsevier Ltd. All rights reserved.
Quanyong Liu - One of the best experts on this subject based on the ideXlab platform.
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In vitro degradation and swelling behaviour of rubbery thermoplastic starch in simulated body and simulated saliva fluid and effects of the degradation products on cells
Polymer Degradation and Stability, 2006Co-Authors: Rui Shi, Quanyong Liu, Yanming Han, Dafu Chen, Tao Ding, Wei TianAbstract:Degradation in vitro is of importance in implanted biological industry. This research investigated the swelling and degradation behaviours of glycerol plasticized thermoplastic starch (GTPS) in simulated body fluid (SBF) and simulated saliva fluid (SSF), respectively. The weight loss, swelling degree and linear extensibility as a function of time were measured. Changes in the morphology (SEM), chemical structure (FT-IR), Crystal Property (XRD) and thermogravimetic Property (TG) during degradation were also investigated. Results show that the degradation in SSF was much quicker than that in SBF. About 1 h was needed for the swelling equilibrium in SBF, which was a little quicker than that in SSF. In alkaline solution the swelling speed and the swelling degree were larger than those in neutral and acidic solutions. The degradation in SBF was typical bulk degradation. In SSF the surface and bulk degradation took place synchronously, but the surface degradation played an important role in the first 2 h. Results from FT-IR and XRD suggest that the glycosidic linkages in starch chains were broken and the Crystal structure in GTPS was destructed during degradation. Cytotoxicity test was used to investigate the effects of the short-term extracted dilutions and long-term degradation products on the cells, which illustrates that the degradation products not only had non-toxicity but also accelerated the cells' growth. © 2006 Elsevier Ltd. All rights reserved.