## 4 Patterning towards Devices: Conventional and Unconventional Methods  
In the last 10 years, the advancements of material chemistry in manufacturing highly functional polymer based nanocomposites have merged with the need of microelectronic industry to fabricate advanced components with high added value properties, reduced operation time and low cost. Such components can be of interest for integrated and miniaturized devices or MEMS systems for large commercial opportunities and near-term applications (_i.e.,_ microcircuitity, computation, optical- and tele-communication, bio/sensing, actuation, photonic, biomedicine and biochemistry) [136]. As a consequence, the microelectronic industry has focused their attention both on advancing pre-exiting conventional fabrication methods and implementing innovative techniques for processing structurale polymer (resist) based nanocomposites [136]. At the same time, original chemical protocols have been able to convey the functionalities of both nanopowders and colloidal NPs to polymeric materials without inherent properties that are used as resist in conventional microfabrication processes. Such innovative functional resists are designed to preserve the mechanical and rheological properties suited for fabricating components, to allow the fabrication of high aspect ratio structures and extend their applicability towards novel advanced MEMS and miniaturized devices.  
At present, the patterning techniques commonly used for micro and/or nano machining resist based nanocomposite materials can be divided in two main classes: mask-based and mask-less methods. The former rely basically on radiation source lithography methods, the latter on a variety of approaches, ranging from block-copolymer lithography, to laser scanning, from inkjet printing to nanoimprinting lithography. Such techniques allow the fabrication of high technologically impact components characterized by high added value properties as durability, design flexibility and geometrical complexity [137].  
It has been reviewed in the previous section how the most common chemical protocols used for manufacturing structural nanocomposite materials consist of _ex situ_ and _in situ_ procedures. The former approach enables the direct incorporation of commercial micro- and nano-sized powders or pre-synthesized colloidal NPs in a pre-existing polymer formulation, by means of a common solvent. This is typically selected as a function of its characteristics (polarity, viscosity and vapor tension), compatibility with the machining processing conditions and capability to preserve the original NC functionalities. These procedures appear to be very convenient, in particular when resists are used as organic host, for preserving the polymer structurability. Indeed the processing parameters could be detrimentally affected by chemical modifications of the resist component and chemical reactions promoted by the NP surface [138] and/or capping layer [139]. On the other hand, the _in situ_ procedure relays on the generation of functional NPs in the resist, by using an embedded precursor which is activated for the NP nucleation and growth during the patterning of the resist. However, such an approach typically suffers from the limited control of the NP crystalline quality, size distribution and shape.  
The next sections will provide a brief introduction of the most commonly used machining techniques for polymer based nanocomposites, together with a focus on recent advancements in manufacturing nano/microcomponents for MEMS and NEMS systems and miniaturized devices.