A Brief Overview on Ferrite (Fe₃O₄) Based Polymeric Nanocomposites: Recent Developments and Challenges
Pages 184-204
O.P. Bajpai, D.K. Setua and S. Chattopadhyay

DOI: http://dx.doi.org/10.6000/1929-5995.2014.03.04.1

Published: 02 January 2015

Abstract: In this article, we have mainly discussed about ferrite (Fe₃O₄)and its polymer based nanocomposites. Ferrite particles have become an important research material because of their vast applications in the field of biotechnology, magnetic resonance imaging (MRI), and data storage.It has been observed that ferrite Fe₃O₄particles show best performance for size less than 10-30 nm. This happens due to the super paramagnetic nature of such particles. In super paramagnetic range these particles exhibit zero remanence or coercivity. Therefore, various properties of ferrite (Fe₃O₄) nanoparticlesand its polymer nanocomposites are very much dependent on the size, and distribution of the particles in the polymeric matrix. Moreover, it has been also observed that the shape of the nanocrystals plays important role in the determination of their fundamental properties. These particles show instability over longer times due to the formation of agglomerates generated by high surface energies. Therefore, protection strategies such as grafting and coatings with silica/carbon or polymers have been developed to stabilize them chemically. Recently, silylation technique is mainly used for the modification of nanoparticles. Experimentally, it has been observed that nanocomposites composed ofpolymer matrices and ferriteshowed substantial improvements in stiffness, fracture toughness, sensing ability (magnetic as well as electric), impact energy absorption,and electro-catalytic activities to bio-species.

An Overview of Mechanical Tests for Polymeric Biomaterial Scaffolds Used in Tissue Engineering
Pages 168-178
Oscar Robles-Vazquez, Ignacio Orozco-Avila, Juan C. Sánchez-Díaz and Elena Hernandez

DOI: http://dx.doi.org/10.6000/1929-5995.2015.04.04.1

Published: 12 January 2016

Abstract: Mechanical characterization of polymeric biomaterial scaffolds is essential to allow biomaterials that interface with tissues and tissue engineered constructs to be developed with appropriate mechanical strength. However, the fragility of these materials makes their mechanical characterization in a quantitative manner highly challenging. Here we report an overview of testing techniques for the characterization of mechanical properties of films, membranes, hydrogels and fibers commonly used as scaffolds in tissue engineering applications.

A Simple and Efficient Approach to Cellulose/Silica Composite Aerogel with High Silica Utilization Efficiency
Pages 56-61
Chong Lin, Ang Li, Yang Cao and Lingbin Lu

DOI: http://dx.doi.org/10.6000/1929-5995.2015.04.01.7

Published: 17 April 2015

Abstract: Cellulose aerogel is a fascinating material with high porosity, low density and biocompatibility. However, cellulose aerogel lacks sufficient thermal stability. Recombination between cellulose aerogel with silica is efficacious for enhance the cellulose aerogel’s thermal stability.This work described a simple and efficient approach to the cellulose/silica composite aerogel via a dropwise manner, using tetraethoxysilane as silicon source and NaOH solution as cellulose solvent. The result showed that the thermal stability of cellulose aerogel was enhanced by introducing silica. And by this manner, the utilization efficiency of silica was up to 95%. The composite aerogel had a low density and a high porosity, which promised the material a good heat insulation performance, and the thermal conductivity of the composite aerogel was low to 0.0161W/(m·K). Moreover, by adjusting cellulose concentration and tetraethoxysilane amount, the density, porosity and thermal conductivity of the composite aerogel could be controlled. This work contributed to improving the utilization efficiency of silica for the composite aerogel with better performances.

Assembly of Ordered Polystyrene Nanoparticles on Self-Assembled Monolayers
Pages 202-209
Ortal Lidor-Shalev, Hagit Aviv and Yitzhak Mastai

DOI: http://dx.doi.org/10.6000/1929-5995.2015.04.04.5

Published: 12 January 2016

Abstract: Spontaneous assembly of nanoparticles onto a surface is a promising bottom-up concept for the fabrication of new functional materials that can be used for various applications in the nanotechnology. In this paper, we describe a system based on gold/polystyrene (Au/PS) Janus particles arranged onto Au self-assembled monolayer (SAM) of 1-dodecanthiol (NDA). The micro-size Au/PS Janus particles are self-assembled onto Au surface and are dissolved into polystyrene (PS) nanoparticles. The SAM of NDA plays two different roles; it dissolves the original Au/PS Janus particles and organizes the PS nanoparticles onto the Au surface. Overall, our proposed method for the assembly of large-scale area nanoparticles can be extended for further uses in the surface science.