Printing technologies have been demonstrated to be highly efficient and compatible with polymeric materials (both inks and substrates) enabling a new generation of flexible electronics applications. Conductive flexible polymers are a new class of materials that are prepared for a wide range of applications, such as photovoltaic solar cells, transistors molecular devices, and sensors and actuators. There are many possible printing techniques. This chapter provides an opportunity to review the most common printing techniques used at the industrial level, the most commonly used substrates and electronic materials, giving an overall vision for a better understanding and evaluation of their different features. Several technological solutions (contact/noncontact) and its critical challenges are also presented. Inkjet Printing Technology (IPT) has been receiving a great attention and therefore higher focus is given to this technology. An overview of IPT is presented to evidence its importance and potential as a key-technology on the research field for printed electronics development, as well as on large scale industrial manufacturing. A background and a review on prior work are presented along with used materials, developed applications and potential of IPT technology. The main features of the different printing technologies, advantages and main challenges are also compared.

The elastic response of vertically aligned-carbon nanotube/polydimethylsiloxane (A-CNT/PDMS) nanocomposites is presented in this study and related to the underlying aligned-CNT morphology. Multiwalled carbon nanotubes (MWCNTs) at 1% V_f are embedded in a flexible substrate of PDMS to create a flexible polymer nanocomposite (PNC). The PNC properties are evaluated using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and tensile mechanical tests, and the full linearly elastic constitutive relation is established for such a PNC. The results suggest that the CNTs retain the alignment after wetting and curing of PDMS. PDMS is significantly modified by the reinforcing aligned-CNT fibers, demonstrating non-isotropic (as opposed to the isotropic neat PDMS) elastic properties all different from PDMS (Young's modulus of 0.8 MPa), including an anisotropy ratio of 4.8 and increases in the modulus of A-CNT/PDMS over PDMS by more than 900% and 100%, in the CNT longitudinal and transverse directions, respectively. This study reports the first full constitutive relation that may be useful in modeling PNCs as composites or as elements of hierarchical nanoengineered composites, particularly PDMS-CNT PNCs are envisioned as elements in biomedical devices such as pressure transducers and energy harvesters.

Phosphorus-doped amorphous-silicon thin-film micromachined mechanical bridge resonators are processed at low temperatures $\text{(⩽110\hspace{0.05em}°}\mathrm{C})$ on glass substrates. The microelectromechanical structures are electrostatically actuated, and the resulting deflection is monitored optically. Resonance frequencies in the megahertz range are observed with quality factors up to 5000 when measured in vacuum. The energy dissipation processes in amorphous-silicon thin-film microbridges are discussed. The dominant intrinsic dissipation mechanism is surface loss.

Microneedles (MNs) have been extensively explored in the literature as a means to deliver drugs in the skin, surpassing the stratum corneum permeability barrier. MNs are potentially easy to produce and may allow the self-administration of drugs without causing pain or bleeding. More recently, MNs have been investigated to collect/assess the interstitial fluid in order to monitor or detect specific biomarkers. The integration of these two concepts in closed-loop devices holds the promise of automated and minimally invasive disease detection/monitoring and therapy. These assure low invasiveness and, importantly, open a window of opportunity for the application of population-specific and personalised therapies.

The pull-in voltage of one- and two-degrees-of-freedom (DOF) structures has been symbolically and numerically analyzed with respect to drive mode dependence and hysteresis. Moreover, the time and temperature stability has been investigated and tested. Modeling results have been applied in the design of both folded-spring-suspended 1-DOF structures and single-side-clamped 2-DOF beams with a nominal pull-in voltage in the 5-10 V range and fabricated in an epi-poly process. Asymmetrically driven structures reveal pull-in close to the value predicted by the model (V/sub pi/ 1-DOF is 4.65 V analytically simulated and 4.56 V measured; V/sub pi/ 2-DOF is 9.24 V analytically simulated, 9.30 V in FEM and 9.34 V measured). Also the hysteresis is in close agreement (release voltage, V/sub r/, 1-DOF is 1.41 V analytically simulated and 1.45 V measured; V/sub r/ 2-DOF is 9.17 V analytically simulated, 9.15 V in FEM and 9.27 V measured). In symmetrically operated devices the differences between the computed and measured V/sub pi/ and V/sub r/ are much larger and are due to process dependencies, which make these devices very suitable for process monitoring. The 2-DOF asymmetrically operated device is the most suitable for MEMS-based voltage reference. The stability in time is limited by charge build-up and calls for a 100-hour initial burn-in. Temperature dependence is -100 /spl mu/V/K at V/sub pi//spl ap/5 V, however, is calculable and thus can be corrected or compensated.