Study of Composite Structures Based on a Porous Silicon Matrix and Nanoparticles Ag/Zno Used as Non-Invasive Highly Sensitive Biosensor Devices

In this work composite structures based on a porous silicon were obtained and studied. Porous matrices were formed by electrochemical etching in aqueous solutions of hydrofluoric acid. Based on the obtained substrates, por-silicon (Si)/silver (Ag) and por-Si/zinc oxide (ZnO) composite structures were formed. These composites were functionalized by various methods (electro (E)-, thermo (T)-, electrothermal exposure) as a result of which the structures were modified. When studying the samples by scanning electron microscopy (SEM), it was concluded that silver nanoparticles actively diffused into the pores under these technological modes of functionalization. The por-Si/Ag and por-Si/ZnO composite structures were also studied using the following methods: infrared (IR) spectroscopy and Raman ultrasoft X-ray emission spectroscopy. Also, the photoluminescent characteristics of the samples were studied. Based on the obtained results, it was concluded that functionalization methods actively change the phase composition of structures and the optical properties of composites.

Thick-Section Epoxy Composites

Thick-section composites (TSC) are extensively demanded in many fields, such as aerospace, wind energy, and oil and gas industries. However, the manufacturing process of thick-section thermoset composites (TSSC) encounters significant complexities, such as variations of nonuniform resin flow, exothermal reaction and curing, and dimensional stability through the thickness direction. These process-related nonuniformities are expected to result in through-thickness gradients of mechanical properties and curing-induced deformations, leading to undesirable residual stresses and damage. This chapter introduces the application of TSC and issues related to its manufacturing processes. Methods of TSC are examined and analyzed. Fundamental characteristics of curing kinetics, thermal transfer, and residual stress in TSC will be explained. Research of detailed experiments will be referred for readers for further studies.