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Chaotic behavior in the transient current through thin Aluminum-PMMA-Aluminum films has been analyzed for times ranging up to 30,000s, in the temperature range 293–363K for applied voltages in the range 10–80V. Time series analysis reveals a positive Lyapunov exponent consistently and reproducibly throughout this range. Power law relaxation as reflected by the autocorrelation function and the positive Lyapunov exponent show parallel behaviors as a function of applied electric field.

To ensure the safe operation of many safety critical structures such as nuclear plants, aircraft and oil pipelines, non-destructive imaging is employed using piezoelectric ultrasonic transducers. These sensors typically operate at a single frequency due to the restrictions imposed on their resonant behavior by the use of a single length scale in the design. To allow these transducers to transmit and receive more complex signals it would seem logical to use a range of length scales in the design so that a wide range of resonating frequencies will result. In this paper, we derive a mathematical model to predict the dynamics of an ultrasound transducer that achieves this range of length scales by adopting a fractal architecture. In fact, the device is modeled as a graph where the nodes represent segments of the piezoelectric and polymer materials. The electrical and mechanical fields that are contained within this graph are then expressed in terms of a finite element basis. The structure of the resulting discretized equations yields to a renormalization methodology which is used to derive expressions for the non-dimensionalized electrical impedance and the transmission and reception sensitivities. A comparison with a standard design shows some benefits of these fractal designs.

Cadmium sulphide (CdS) nanocrystallites were prepared by sulphuration route with capping in polyethylene oxide (PEO) polymer matrix. It is found that PEO could provide a confined environment for particle nucleation and growth of CdS nanocrystallites. The scanning electron microscopy (SEM) with energy dispersive analysis by X-ray (EDAX) studies confirms the presence of CdS nanocrystallites in polymer matrix. X-ray diffraction (XRD) studies and transmission electron microscopy (TEM) selected area diffraction (SAD) patterns show that these crystallites have hexagonal structure. The TEM and UV-Visible absorption studies indicate uniform size distribution having size around 2.3 nm and band gap of 2.7 eV. X-ray photoelectron spectroscopy (XPS) studies reveal that core level energy positions of the Cd is shifted towards the lower binding energy and has similar chemical environment to that of bulk CdS.

A novel and shape-controlled synthesis method for uniformly-shaped poly(p-phenylenediamine) (PpPD) microparticles was developed using (NH₄)₂S₂O₈ (APS) as an oxidant. The results demonstrated that the morphologies of PpPD varied from nanofibers to nanospheres and nest-like microspheres by tuning the pH of solution. Tiny pH change leads to the significant change in product morphology. The structure of microspheres is similar to graphene which was first discovered. Further study showed that the PpPD nanofibers were dimer. The difference in the structure of PpPD nanofibers and nanospheres (microspheres) resulted in different solubility in water. The nanosized oligomer crystallites served as starting templates for the nucleation of PpPD nanofibers. Further growth of nanofibers was proceeded by the self-organization of phenazine units or their blocks located at the ends of the PpPD chains.

The electrochemical properties of poly sodium 4-styrenesulfonate intercalated graphite oxide (PSSGO) have been investigated in a 1 M H₂SO₄ electrolyte. We observed capacitor behavior at scan rate of 1–25 mV/s in a cyclic voltammetry. Specific capacitance obtained from galvanostatic charge and discharge measurements were 6 F/g to 102 F/g at 1 A/g to 0.1 A/g, respectively. The specific capacitance of PSSGO is relatively high compared to that of the precursor graphite oxide in which the specific capacitance was 11–20 F/g at 0.03 A/g. Capacitance retention was 73% after 3000 cycles, proving reliable cyclic stability up to 3000 cycles.

Amphiphilic polymer carriers (PEG–St–$R$) were prepared from cassava starch and their pH response was investigated. First, hydrophobic tapioca starch polymer (St–$R$) was prepared with octyl acyl as the hydrophobic group. The hydrophilic group polyethylene glycol (mPEG) was then introduced into the polymer by esterification to produce amphiphilic tapioca starch polymer (PEG–St–$R$). Its self-assembly behavior was characterized using fluorescent probes. The morphology of PEG–St–$R$ was investigated by transmission electron microscopy (TEM). Loading of the anti-cancer drug curcumin was used to assess the delivery and slow-release performance of the amphiphilic tapioca starch polymer. Cumulative drug release was explored at various pH conditions, with the greatest release from drug-loaded micelles being observed under acidic conditions and stable in a neutral environment. These results provide a theoretical basis for the preparation of pH-responsive nanomicelle carriers, and a platform for the preparation of novel amphiphilic starch-based polymers.