Carvacrol/ß-cyclodextrin inclusion complex as a fumigant to control decay caused by Penicillium digitatum on Shatangju mandarin slices.

Preservation and microorganism control of fresh-cut fruit pose a persistent challenge in the food industry. To address this issue, we prepared a ß-cyclodextrin (ß-CD) inclusion complex containing carvacrol using a coprecipitation method and employed it for the non-contact fumigation of fresh-cut Shatangju mandarin slices. This biodegradable and safe preservative offers an effective means to combat spoilage and ensure product quality. We confirmed the formation of the encapsulated structure of the inclusion complex through various characterization methods, including scanning electron microscopy (SEM), Fourier transform-infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and differential thermal analysis (DTA). We also demonstrated the inhibitory effect of this preservative on Penicillium digitatum and its associated spoilage both in vitro and in vivo. The incidence and severity were significant lower in the inclusion complex-treated group (75.0% and 46.7%, respectively) compared to the group treated with pure carvacrol (100% and 69.2%, respectively). In addition, fruit freshness parameters and sensory evaluation showed that the inclusion complex treatment effectively maintained the overall quality of the fruit and achieved the highest consumer acceptance.

Strategy based on multiplexed brush architectures for regulating the spatiotemporal immobilization of biomolecules.

Functional surfaces that enable both spatial and temporal control of biomolecules immobilization have attracted enormous attention for various fields including smart biointerface materials, high-throughput bioarrays, and fundamental research in the biosciences. Here, a flexible and promising method was presented for regulating the spatiotemporal arrangement of multiple biomolecules by constructing the topographically and chemically diverse polymer brushes patterned surfaces. A series of polymer brushes patterned surfaces, including antifouling brushes patterned surface, epoxy-presenting brushes patterned surface without and with antifouling background layer, were fabricated to control the spatial distribution of protein and cell adhesion through specific and nonspecific means. The fluorescence measurements demonstrated the effectiveness of spatially regulating the density of surface-immobilized protein through controlling the areal thickness of the poly (glycidyl methacrylate) (PGMA) brush patterns, leading to various complex patterns featuring well-defined biomolecule concentration gradients. Furthermore, a multiplexed surface bearing epoxy groups and azido groups with various areal densities was fabricated for regulating the spatiotemporal arrangement of different proteins, enabling binary biomolecules patterns with higher degrees of functionality and complexity. The presented strategy for the spatiotemporal control of biomolecules immobilization would boost the development of dynamic and multifunctional biosystems.

The Establishment of Thermal Conductivity Model for Linear Low-Density Polyethylene/Alumina Composites Considering the Interface Thermal Resistance.

An optimized thermal conductivity model of spherical particle-filled polymer composites considering the influence of interface layer was established based on the classic series and parallel models. ANSYS software was used to simulate the thermal transfer process. Meanwhile, linear low-density polyethylene/alumina (LLDPE/Al2O3) composites with different volume fractions and Al2O3 particle sizes were prepared with the continuous mixer, and the effects of Al2O3 particle size and volume fraction on the thermal conductivity of the composites were discussed. Finally, the test result of the thermal conductivity was analyzed and compared with ANSYS simulations and the model prediction. The results proved that the thermal conductivity model considering the influence of the interface layer could predict the thermal conductivity of LLDPE/Al2O3 composites more precisely.

The Entangled Conductive Structure of CB/PA6/PP MFCs and Their Electromechanical Properties.

In this work, carbon black (CB)/polyamide 6 (PA6)/polypropylene (PP) microfibrillar composites (MFCs) were fabricated through an extrusion (hot stretching) heat treatment process. The CB-coated conductive PA6 microfibrils with high aspect ratio were in situ generated as a result of the selective accumulation of CB at the interface. At the proper temperature, a 3D entangled conductive structure was constructed in the PP matrix, due to topological entanglement between these conductive microfibrils. This unique conductive structure provided the PP composites with a low electrical conductivity percolation threshold. Moreover, the electromechanical properties of conductive MFCs were investigated for the first time. A great stability, a high sensitivity and a nice reproducibility were achieved simultaneously for CB/PA6/PP MFCs. This work provides a universal and low-cost method for the conductive polymer composites' (CPCs) fabrication as sensing materials.

Deformation-Induced Crystallization Behavior of Isotactic Polypropylene Sheets Containing a ß-Nucleating Agent under Solid-State Stretching.

The deformation-induced crystallization of an isotactic polypropylene (iPP) sheet containing a ß-nucleating agent was evaluated. The phase transformation of the ß-modifications was investigated and the crystal morphology was observed at room temperature after stretching at different temperatures. The results showed that the crystallinity increased after solid-state stretching. When the stretching temperature was below the initial crystallization temperature, stretching deformation promoted the orientation of amorphous molecular chains. When the deformation temperature exceeded the crystallization temperature, part of the ß-modifications underwent a phase transformation process and was stretched into a shish-kebab structure. However, once the stretching temperature was close to the melting point, the ß-modifications melted and recrystallized, and the shish-kebab structure underwent stress relaxation due to poor thermal stability, transforming into α-modifications. It was revealed that the crystal phase transformation mechanism of the ß-modifications was based on the orientation of the molecular chains between the adjacent lamellae. In addition, the shish-kebab cylindrite structure played an important role in modifying the tensile and impact properties of the iPP sheet. The tensile and impact strengths increased by as much as 34% and 126%, respectively.

The Formation of a Highly Oriented Structure and Improvement of Properties in PP/PA6 Polymer Blends during Extrusion-Stretching.

During the "slit die extrusion-hot stretching" process, highly oriented polyamide 6 (PA6) dispersed phase was produced and retained in the polypropylene (PP) matrix directly. By adjusting the stretching forces, the PA6 spherical phase evolved into the ellipsoid, rod-like microfibril with a decreasing average diameter; then, the PA6 microfibrils broke. Moreover, the effects of the PA6 phases formed in the process of the microfibrillation on PP's crystallization behaviors were studied systematically. As the stretching forces increased, the crystallization ability and orientation degree of PP crystals improved significantly. Differential scanning calorimetry and polarizing optical microscopy confirmed the formation of PP spherulite, fan-shaped lamellae and a transcrystalline layer under the induction of the PA6 phases with different morphology. In the PP/PA6 microfibrilar composites (MFCs), PP crystals showed smaller average size, more crystals and stronger interface adhesion due to more excellent heterogeneous nucleation ability of the PA6 microfibrils, which made contributions to the improvement of the melt elasticity responses and oxygen barrier properties of the PP/PA6 polymer blends.

Spatiotemporal control of polymer brush formation through photoinduced radical polymerization regulated by DMD light modulation.

Spatially arranged polymer brushes provide the essential capability of precisely regulating the surface physicochemical and functional properties of various substrates. A novel and flexible polymer brush patterning methodology, which is based on employing a digital mirror device (DMD)-based light modulation technique to spatiotemporally regulate a surface-initiated photoinduced atom transfer radical polymerization (photo-ATRP) process, is presented. Various characterization techniques confirm that the spatially and/or temporally controlled brush formation results in complex PEG-derived brush patterns in accordance with a customized digital image design. A series of step-and-exposure strategies, including in situ multiple exposure, dynamic multiple exposure and dynamic sequential exposure, are developed to implement spatiotemporal regulation of the photo-ATRP process, leading to complex patterned and gradient brushes featuring binary functionalities, pyramid nanostructures and radial directional chemical gradients. Moreover, tunable and radial directional concentration gradients of various biomacromolecules (e.g., streptavidin) are obtained through preparation of height gradients of azido-functionalized brushes and subsequent orthogonal chemical activation aimed at specific protein immobilization. Finally, a unidirectional concentration gradient of fibronectin, surrounded by non-fouling PEG brushes, is fabricated and applied for human umbilical vein endothelial cell (HUVEC) adhesion experiments, whose preliminary results indicate gradient-dependent cell adhesion behavior in response to the concentration gradient of fibronectin. The presented fabrication technique could be integrated with microfluidic devices for sensors and bio-reactors, paving the way for novel approaches for lab-on-a-chip technologies.

Effects of Solid-State Stretching on Microstructure Evolution and Physical Properties of Isotactic Polypropylene Sheets.

The microstructure evolution of an isotactic polypropylene (iPP) sheet during solid-state stretching was studied. The transition of the spherulites-cylindrites was evaluated using in-situ two-dimensional wide-angle and small-angle X-ray scattering methods. The crystallinity of stretched iPP sheets was characterized by differential scanning calorimetry. The crystal morphology was observed by means of scanning electron microscopy. It was found that the differences of crystal microstructure of the iPP sheet depended on the stretching strain, which promoted the orientation of molecular chains. Amorphous molecular chains in the spherulites oriented and formed into a mesophase near the yield point, and the partially ordered mesophase was further stretched to form an oriented cylindrite structure after the yield point. The highest relative content of cylindrites appeared at 15% strain. Notably, as the amorphous phase embedded into the lamellae layer, the crystal size decreased with the increase of strain, which indicated that the crystallinity of the stretched iPP sheet was much higher than that of unstretched iPP sheet. The induced cylindrites structure played a more important role in improving the mechanical properties and heat resistance of iPP sheets. Compared with the unstretched iPP sheets, the tensile strength increased by 28%, the notch impact toughness significantly increased by 78%, and the vicat softening point increased from 104 to 112 °C.