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a) b - École Polytechnique de Montréal

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APPENDIX II<br />

A- 2 Estimation of Conductivity of Porous Conductive<br />

Devices by Semi-Empirical Mo<strong>de</strong>ls<br />

Assembly of dimensional structures through the templating of multilayers onto 3D nanometer to<br />

micrometer scale objects was one of the most outstanding strategy modifications for LbL<br />

preparation. A few works have been <strong>de</strong>voted to <strong>de</strong>veloping 3D structures as the substrate in other<br />

areas of science such as drug <strong>de</strong>livery, but to date 3D templates have not been used for<br />

fabrication of LbL conductive multilayers. The pioneering works in which the LbL films were<br />

assembled on a 3D colloidal core(Caruso, Caruso, et al., 1998; Caruso, Caruso, & Mohwald,<br />

1999) and 3D nano-sized porous templates(Hou, Harrell, Trofin, Kohli, & Martin, 2004) were<br />

carried out for controlled release, encapsulation of guest substances, and other purposes(Caruso<br />

& Schuler, 2000; Hou, et al., 2004; Park, Deng, & Advincula, 2005; Schnei<strong>de</strong>r & Decher, 2004;<br />

Volodkin, Petrov, Prevot, & Sukhorukov, 2004). Fabrication of a highly-controlled porous 3D<br />

substrate on which the LbL multilayer can be <strong>de</strong>posited is of great importance, whereas<br />

controlling the surface area can influence on the absorbed multilayer(Caruso, 2003). Applying a<br />

3D structure enables us to not only manipulate the function of singular LbL multilayer films, but<br />

to create highly-controlled complex structures with a hierarchy of or<strong>de</strong>r and function that can be<br />

used to create <strong>de</strong>vices and microsystems with special properties. The effect of porosity on<br />

mechanical, physical, and electrical properties of porous materials has been studied. For sintered<br />

metals, the presence of pores causes a <strong>de</strong>crease in strength and ductility and a <strong>de</strong>trimental effect<br />

on conductivity and magnetic properties. Hence, the study of the relationship between<br />

microstructure, and particularly porosity, of conductive porous samples and conductivity is of<br />

great importance.<br />

In this part of the work, a semi-empirical mo<strong>de</strong>l is obtained to calculate the conductivity of<br />

porous samples represented in Chapter 5 as a function of porosity and conductivity of the pure<br />

246

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