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Hypothesis The microfluidic technology can drive molecules to organize into aggregates with nano-structures, and gives a possibility to control aggregate morphologies by adjusting hydrodynamic parameters of microfluidics. COMSOL Multiphysics is a useful software to simulate the mixing situation of solutions in microfluidic. Here, experiments and simulation are combined to study the self-assembly of gradient copolymers in the microfluidic device. Experiments Fluorinated gradient copolymers self-assembled in a three-dimensional co-flow focusing microfluidic device (3D CFMD). Hydrodynamic parameters of 3D CFMD were adjusted to control morphologies and the sizes of copolymer aggregates. A simulation software, COMSOL Multiphysics, was used to simulate the mixing and diffusion of outer phase stream and inner phase stream to explore the mixing kinetics of two streams in the microchannels. Findings 3D CFMD offered a novel platform for the continuous and controllable self-assembly of fluorinated gradient copolymer. Various morphologies of copolymer aggregates were obtained in 3D CFMD, but just spherical micelles were formed by a traditional solvent-inducing method. The flow velocity, initial water content of outer-phase stream, and the copolymer concentration of inner-phase stream had great effects on the morphology and size of copolymer aggregates. The simulation results made us a better understanding on the microfluidic self-assembly. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effects of the total biopolymer (egg white protein - EW and hydroxypropylmethylcellulose – HPMC) concentration (1.4–5.6 g/100 g of sugar) and EW/HPMC ratio (2/1 to 18/1 g/g) on the apparent viscosity before whipping, foaming capacity (density and overrun) and foam rheological properties (G’, G” and δ) of sugar/EW/HPMC mixtures using a central composite rotatable design (CCRD). The conditions to obtain intermediate apparent viscosity, high foaming capacity, elastic and solid behaviour were total biopolymer concentration 5.0 g/100 g of sugar and EW/HPMC ratio 14/1 (g/g). Under these conditions, experiments were carried out to evaluate the effect of interactions between EW and HPMC at pH 3.0, 4.5 and 6.0 on the foaming and rheological properties. The greatest foaming capacity, elastic and solid behaviour, with no liquid drainage, were obtained at pH 3.0. At pH 4.5, foams possessed monodisperse bubble size distribution and viscoelastic behaviour, leading to better stability with respect to disproportionation and coalescence compared to foams at pH 3.0. At pH 6.0, foam showed the poorest foaming properties and viscous behaviour. The interactions between EW and HPMC in aerated confectionery at different pH affect foaming and rheological properties. [ABSTRACT FROM AUTHOR]

The sedimentation of micro and nanosized plastics is of considerable environmental relevance and the need to assess its sublethal effects to biota increasingly recognized. In their majority, as bottom, non-selective grazers, independent-feeding young life stages of amphibians, an already severely endangered worldwide group, may be particularly vulnerable to sedimented plastics. Alongside, they may be good model organisms for the assessment of the effects of micro(nano)plastics (MNPs) through ingestion. However, to our knowledge, few studies have assessed amphibians' exposure to MNPs through contaminated food or its effects in feeding behaviour assays. The available studies reveal a lack of consistent methodology: organisms, food type, media of exposure, or exposure conditions (temperature and light) in the assessment of effects. This perspective article, will address major differences found in the available studies, identifying type, size and concentrations of the polymers tested, species, and observed effects, aiming to highlight the importance of feeding exposure assays when attempting to evaluate the effect of MNPs in amphibians. [ABSTRACT FROM AUTHOR]

The sedimentation of micro and nanosized plastics is of considerable environmental relevance and the need to assess its sublethal effects to biota increasingly recognized. In their majority, as bottom, non-selective grazers, independent-feeding young life stages of amphibians, an already severely endangered worldwide group, may be particularly vulnerable to sedimented plastics. Alongside, they may be good model organisms for the assessment of the effects of micro(nano)plastics (MNPs) through ingestion. However, to our knowledge, few studies have assessed amphibians' exposure to MNPs through contaminated food or its effects in feeding behaviour assays. The available studies reveal a lack of consistent methodology: organisms, food type, media of exposure, or exposure conditions (temperature and light) in the assessment of effects. This perspective article, will address major differences found in the available studies, identifying type, size and concentrations of the polymers tested, species, and observed effects, aiming to highlight the importance of feeding exposure assays when attempting to evaluate the effect of MNPs in amphibians. [ABSTRACT FROM AUTHOR]

Novel poly(alkoxysilane)s with high oil and organic solvent absorbencies were prepared by a bulk polymerization technique via the condensation of 1,3-benzenedimethanol with different lengths of alkoxysilanes at 160 °C without using a catalyst. The influence of the length of the alkoxysilane on the polymer properties and swelling ratios was investigated. Swelling experiments in various solvents indicated that these cross-linked poly(alkoxysilane)s can be used as absorbents for oils and oil-derived organic solvents. The swelling features of the poly(alkoxysilane)s were determined by solvent absorption tests, swelling kinetics experiments, and desorption kinetics measurements. The absorption capacities of the poly(alkoxysilane)s were 50–725% for various organic solvents and oil derivatives such as gasoline and diesel. The structural and thermal properties of the cross-linked poly(alkoxysilane) polymers were determined by FTIR, solid-state 13 C and 29 Si cross-polarization magic angle spinning (CP-MAS) NMR, and thermal gravimetric analysis (TGA). [ABSTRACT FROM AUTHOR]

Biopolymers are considered a potential alternative to conventional chemical polymers because of their ease of biodegradability, high efficiency, non-toxicity and non-secondary pollution. Recently, extracellular polymeric substances (EPS, biopolymers produced by the microorganisms) have been recognised by many researchers as a potential flocculent for their applications in various water, wastewater and sludge treatment processes. In this context, literature information on EPS is widely dispersed and is very scarce. Thus, this review marginalizes various studies conducted so far about EPS nature-production-recovery, properties, environmental applications and moreover, critically examines future research needs and advanced application prospective of the EPS. One of the most important aspect of chemical composition and structural details of different moieties of EPS in terms of carbohydrates, proteins, extracellular DNA, lipid and surfactants and humic substances are described. These chemical characteristics of EPS in relation to formation and properties of microbial aggregates as well as degradation of EPS in the matrix (biomass, flocs etc) are analyzed. The important engineering properties (based on structural characteristics) such as adsorption, biodegradability, hydrophilicity/hydrophobicity of EPS matrix are also discussed in details. Different aspects of EPS production process such as bacterial strain maintenance; inoculum and factors affecting EPS production were presented. The important factors affecting EPS production include growth phase, carbon and nitrogen sources and their ratio, role of other nutrients (phosphorus, micronutrients/trace elements, and vitamins), impact of pH, temperature, metals, aerobic versus anaerobic conditions and pure and mixed culture. The production of EPS in high concentration with high productivity is essential due to economic reasons. Therefore, the knowledge about all the aspects of EPS production (listed above) is highly essential to formulate a logical and scientific basis for the research and industrial activities. One of the very important issues in the production/application/biodegradation of EPS is how the EPS is extracted from the matrix or a culture broth. Moreover, EPS matrix available in different forms (crude, loosely bound, tightly bound, slime, capsular and purified) can be used as a bioflocculant material. Several chemical and physical methods for the extraction of EPS (crude form or purified form) from different sources have been analyzed and reported. There is ample information available in the literature about various EPS extraction methods. Flocculability, dewaterability and biosorption ability are the very attractive engineering properties of the EPS matrix. Recent information on important aspects of these properties qualitatively as well as quantitatively has been described. Recent information on the mechanism of flocculation mediated by EPS is presented. Potential role of EPS in sludge dewatering and biosorption phenomenon has been discussed in details. Different factors influencing the EPS ability to flocculate and dewaterability of different suspensions have been included. The factors considered for the discussion are cations, different forms of EPS, concentration of EPS, protein and carbohydrate content of EPS, molecular weight of EPS, pH of the suspension, temperature etc. These factors were selected for the study based upon their role in the flocculation and dewatering mechanism as well the most recent available literature findings on these factors. For example, only recently it has been demonstrated that there is an optimum EPS concentration for sludge flocculation/dewatering. High or low concentration of EPS can lead to destabilization of flocs. Role of EPS in environmental applications such as water treatment, wastewater flocculation and settling, colour removal from wastewater, sludge dewatering, metal removal and recovery, removal of toxic organic compounds, landfill leachate treatment, soil remediation and reclamation has been presented based on the most recent available information. However, data available on environmental application of EPS are very limited. Investigations are required for exploring the potential of field applications of EPS. Finally, the limitations in the knowledge gap are outlined and the research needs as well as future perspectives are highlighted. [ABSTRACT FROM AUTHOR]

Abstract: A new inverse technique to characterise the nonlinear mechanical properties of viscoelastic core layers in sandwich panels has been developed based on simple vibration tests. The present methodology allows one to preserve the frequency and temperature dependences of the storage and loss moduli of viscoelastic materials for a wide range of frequencies and to perform a structural analysis using high damping tests. The computational effort has been substantially reduced by using an optimisation based on the planning of the experiments and the response surface technique in order to minimise the error functional. This new inverse technique has been tested and applied to characterise the viscoelastic properties of a 3M damping polymer (ISD-112) used as a core material in sandwich panels. The identified material properties have been verified successfully by comparing structural dynamic parameters obtained from the numerical analysis with experiments. [Copyright &y& Elsevier]