The Effects of Casting and Blending on Properties of Ionomer and the Electromechanical Responses of Ionic Polymer Metal Composite Actuators

As one typical kind of ionic electroactive polymers (iEAPs), ionic polymer metal composites (IPMC) consist of an ionomer and two thin layers of metallic electrode on its both sides. The micro-properties of the ionomer, usually Nafion as the most used ionomer, exert strongly effects on the responses of IPMC actuator. Our works revealed the effects of casting process with different additives (ethylene glycol (EG), dimethyl sulfoxide (DMSO), N, N′-dimethyl formamide (DMF) and N-methyl formamide (NMF)), and blending with sulfonated multi-walled carbon nanotube (sMWCNT) on properties of ionomer and the electromechanical responses of IPMC actuators. Some important properties of casting membrane and sMWCNT/Nafion blending membrane, such as surface morphology, water uptake and ionic exchange capacity, etc., were measured and evaluated. Among the casting membrane-based IPMC actuators, EG based IPMC actuator has larger deformation at 2 V DC voltage. And a trace amount of sMWCNT can improve the performances of IPMCs significantly for realistic applications

Physical Stability of Chestnut Lily Beverages (CLB): Effects of Shear Homogenization on Beverage Rheological Behavior, Particle Size, and Sensory Properties

The processing parameters have a crucial influence on the stability and sensory quality of beverages. The focus of this study is to observe the rheological behavior, particle size distribution, stability, color change, and sensory evaluation of chestnut lily beverages (CLB) at different rotational speeds (0~20,000 rpm) using a high-shear homogeneous disperser. The CLB system exhibited non-Newtonian shear-thinning behavior. As the homogenization speed increased (0~12,000 rpm), the viscosity increased (0.002~0.059 Pa.s). However, when the rotational speed shear continued to increase (12,000~20,000 rpm), the viscosity decreased slightly (0.035~0.027 Pa.s). Under all homogeneous conditions, the turbidity and precipitation fractions were the lowest when the rotational speed was 12,000 rpm: the sedimentation index was lowest at this point (2.87%), and the relative turbidity value of CLB was largest at this point (80.29%). The average beverage particle diameter and ascorbic acid content showed a downward trend at the homogenization speed from 0 to 20,000 rpm, whereas the total soluble solids (TSS) content followed the opposite trend. The results show that these physical properties can be correlated with different rotational speeds of homogenization. This study explained the effect of homogenization speed on CLB properties, which needs to be considered in beverage processing, where high-speed shear homogenization can serve as a promising technique

Effects of low molecular sugars on the retrogradation of tapioca starch gels during storage.

The effects of low molecular sugars (sucrose, glucose and trehalose) on the retrogradation of tapioca starch (TS) gels stored at 4°C for different periods were examined with different methods. Decrease in melting enthalpy (ΔHmelt) were obtained through differential scanning calorimetry analysis. Analysis of decrease in crystallization rate constant (k) and increase in semi-crystallization time (τ1/2) results obtained from retrogradation kinetics indicated that low molecular sugars could retard the retrogradation of TS gels and further revealed trehalose as the best inhibitor among the sugars used in this study. Fourier transform infrared (FTIR) analysis indicated that the intensity ratio of 1047 to 1022 cm-1 was increased with the addition of sugars in the order of trehalose > sucrose > glucose. Decrease in hardness parameters and increase in springiness parameters obtained from texture profile analysis (TPA) analysis also indicated that low molecular sugars could retard the retrogradation of TS gels. The results of FTIR and TPA showed a consistent sugar effect on starch retrogradation with those of DSC and retrogradation kinetics analysis

Carrageenan-Based Pickering Emulsion Gels Stabilized by Xanthan Gum/Lysozyme Nanoparticle: Microstructure, Rheological, and Texture Perspective

In this study, Pickering emulsion gels were prepared by the self-gel method based on kappa carrageenan (kC). The effects of particle stabilizers and polysaccharide concentrations on the microstructure, rheological characteristics, and texture of Pickering emulsion gels stabilized by xanthan gum/lysozyme nanoparticles (XG/Ly NPs) with kC were discussed. The viscoelasticity of Pickering emulsion gels increased significantly with the increase of kC and XG/Ly NPs. The results of temperature sweep showed that the gel formation mainly depended on the kC addition. The XG/Ly NPs addition could accelerate the formation of Pickering emulsion gels and increase its melting temperature (Tmelt), which is helpful to improve the thermal stability of emulsion gels. Cryo-scanning electron microscope (Cryo-SEM) images revealed that Pickering emulsion gel has a porous network structure, and the oil droplets were well wrapped in the pores. The hardness increased significantly with the increase of XG/Ly NPs and kC. In particular, the Pickering emulsion gel hardness was up to 2.9 Newton (N) when the concentration of kC and XG/Ly NPs were 2%. The results showed that self-gelling polysaccharides, such as kC, could construct and regulate the structure and characteristics of Pickering emulsion gel. This study provides theoretical support for potential new applications of emulsion gels as functional colloids and delivery systems in the food industry

<i>R</i>(1047/1022) of TS gel (10%) without or with sugars after refrigerated storage.

<p>(Samples No. 1 is TS gel without sugars and sample Nos. 2, 3 and 4 are TS gel with glucose, sucrose and trehalose, respectively).</p

Retrogradation kinetics parameters of TS gel without or with sugars.

<p>Retrogradation kinetics parameters of TS gel without or with sugars.</p

Retrogradation kinetics parameters of TS gel without or with sugars.

<p>Retrogradation kinetics parameters of TS gel without or with sugars.</p

Hardness and springness of TS gels without or with sugars after storage.

<p>Hardness and springness of TS gels without or with sugars after storage.</p

IR spectra of TS gel (10%) without sugars after refrigerated storage.

<p>(a) Original IR spectra (b) deconvoluted IR spectra (c) peak-fitted IR spectra.</p