Jun Zhang

Bio: Jun Zhang is an academic researcher from Shanghai Jiao Tong University. The author has contributed to research in topics: Tumor microenvironment & Dielectric. The author has an hindex of 11, co-authored 35 publications receiving 477 citations.

Energy storage in ferroelectric polymer nanocomposites filled with core-shell structured polymer@BaTiO3 nanoparticles: understanding the role of polymer shells in the interfacial regions.

Abstract: The interfacial region plays a critical role in determining the electrical properties and energy storage density of dielectric polymer nanocomposites. However, we still know a little about the effects of electrical properties of the interfacial regions on the electrical properties and energy storage of dielectric polymer nanocomposites. In this work, three types of core–shell structured polymer@BaTiO3 nanoparticles with polymer shells having different electrical properties were used as fillers to prepare ferroelectric polymer nanocomposites. All the polymer@BaTiO3 nanoparticles were prepared by surface-initiated reversible-addition–fragmentation chain transfer (RAFT) polymerization, and the polymer shells were controlled to have the same thickness. The morphology, crystal structure, frequency-dependent dielectric properties, breakdown strength, leakage currents, energy storage capability, and energy storage efficiency of the polymer nanocomposites were investigated. On the other hand, the pure polymers ha...

Polypropylene based thermoplastic polymers for potential recyclable HVDC cable insulation applications

Abstract: Thermoplastic materials are highly desirable for power cable insulation application because of their recyclability and ease of processing. They are particularly suitable for high voltage direct current (HVDC) cable insulation because of the absence of byproducts during cable production, which may result in the reduction of undesirable space charge accumulation and the degassing cost. Polypropylene based polymers may have the potential for recyclable thermoplastic cable insulation application because of their high melting temperatures and adjustable mechanical and electrical properties. This work aimed at evaluating the potential of isotactic polypropylenes, propylene-ethylene block copolymers and random copolymers for thermoplastic cable insulation application. We investigated the melting and crystallization behavior, crystal structure, supramolecular structure, mechanical properties, space charge distribution and DC breakdown strength of six different polymers (two isotactic polypropylenes, two block copolymers and two random copolymers). A comprehensive analysis of these parameters indicates that the propylene-ethylene binary random copolymers are more potentially suitable for thermoplastic cable insulation application.

Reducing Interstitial Fluid Pressure and Inhibiting Pulmonary Metastasis of Breast Cancer by Gelatin Modified Cationic Lipid Nanoparticles.

Abstract: Interstitial fluid pressure (IFP) in tumor is much higher than that in normal tissue, and it constitutes a great obstacle for the delivery of antitumor drugs, thus becoming a potential target for cancer therapy. In this study, cationic nanostructured lipid carriers (NLCs) were modified by low molecular weight gelatin to achieve the desirable reduction of tumor IFP and improve the drug delivery. In this way, the chemotherapy of formulations on tumor proliferation and pulmonary metastasis was further improved. The nanoparticles were used to load three drugs, docetaxel (DTX), quercetin (Qu), and imatinib (IMA), with high encapsulation efficiency of 89.54%, 96.45%, and 60.13%, respectively. GNP-DTX/Qu/IMA nanoparticles exhibited an enzyme-sensitive drug release behavior, and the release rate could be mediated by matrix metalloproteinases (MMP-9). Cellular uptake and MTT assays showed that the obtained GNP-DTX/Qu/IMA could be internalized into human breast 4T1 cells effectively and exhibited the strongest cyto...

Nano based drug delivery systems: recent developments and future prospects

Abstract: Nanomedicine and nano delivery systems are a relatively new but rapidly developing science where materials in the nanoscale range are employed to serve as means of diagnostic tools or to deliver therapeutic agents to specific targeted sites in a controlled manner Nanotechnology offers multiple benefits in treating chronic human diseases by site-specific, and target-oriented delivery of precise medicines Recently, there are a number of outstanding applications of the nanomedicine (chemotherapeutic agents, biological agents, immunotherapeutic agents etc) in the treatment of various diseases The current review, presents an updated summary of recent advances in the field of nanomedicines and nano based drug delivery systems through comprehensive scrutiny of the discovery and application of nanomaterials in improving both the efficacy of novel and old drugs (eg, natural products) and selective diagnosis through disease marker molecules The opportunities and challenges of nanomedicines in drug delivery from synthetic/natural sources to their clinical applications are also discussed In addition, we have included information regarding the trends and perspectives in nanomedicine area

Tunneling effect in a polymer/carbon nanotube nanocompositestrain sensor

Abstract: A strain sensor has been fabricated from a polymer nanocomposite with multiwalled carbon nanotube (MWNT) fillers. The piezoresistivity of this nanocomposite strain sensor has been investigated based on an improved three-dimensional (3D) statistical resistor network model incorporating the tunneling effect between the neighboring carbon nanotubes (CNTs), and a fiber reorientation model. The numerical results agree very well with the experimental measurements. As compared with traditional strain gauges, much higher sensitivity can be obtained in the nanocomposite sensors when the volume fraction of CNT is close to the percolation threshold. For a small CNT volume fraction, weak nonlinear piezoresistivity is observed both experimentally and from numerical simulation. The tunneling effect is considered to be the principal mechanism of the sensor under small strains.

Surface-Initiated Controlled Radical Polymerization: State-of-the-Art, Opportunities, and Challenges in Surface and Interface Engineering with Polymer Brushes

Abstract: The generation of polymer brushes by surface-initiated controlled radical polymerization (SI-CRP) techniques has become a powerful approach to tailor the chemical and physical properties of interfaces and has given rise to great advances in surface and interface engineering. Polymer brushes are defined as thin polymer films in which the individual polymer chains are tethered by one chain end to a solid interface. Significant advances have been made over the past years in the field of polymer brushes. This includes novel developments in SI-CRP, as well as the emergence of novel applications such as catalysis, electronics, nanomaterial synthesis and biosensing. Additionally, polymer brushes prepared via SI-CRP have been utilized to modify the surface of novel substrates such as natural fibers, polymer nanofibers, mesoporous materials, graphene, viruses and protein nanoparticles. The last years have also seen exciting advances in the chemical and physical characterization of polymer brushes, as well as an ev...

Carbon Nanotubes Embedded in Oriented Polymer Nanofibers by Electrospinning

Abstract: The electrospinning process was used successfully to fabricate nanofibers of poly(ethylene oxide) (PEO) in which multiwalled carbon nanotubes (MWCNT) are embedded. Initial dispersion of MWCNTs in water was achieved using amphiphiles, either as small molecules (sodium dodecyl sulfate, SDS) or as a high molecular weight, highly branched polymer (Gum Arabic). These dispersions provided separation of the MWCNTs and their individual incorporation into the PEO nanofibers by subsequent electrospinning. The focus of this work is on the development of axial orientations in these multicomponent nanofibers. A theoretical model is presented for the behavior of rodlike particles representing CNTs in electrospinning. Initially the rods are randomly oriented, but due to the sinklike flow in a wedge they are gradually oriented mainly along the stream lines, so that straight CNTs are almost oriented upon entering the electrospun jet. The degrees of orientation of polymer, surfactant, and MWCNT were studied using X-ray dif...