Conductive inks for printed electronics

A silver conductive ink is a functional formulation intended to create printed tracks or electrodes. Its behaviour depends on the grade, deposit, substrate, printing conditions and curing cycle. Applicable electrical data must be checked in the technical data sheet for the selected grade and on the project assembly.

A dielectric ink or varnish is a printable insulating formulation used between conductive layers in a circuit architecture. Select the grade with the associated inks, substrate and curing conditions. Insulation, adhesion and processing characteristics must be checked in the technical documentation for each grade.

Piezoelectric inks contain PZT (lead zirconate titanate) or PVDF particles dispersed in a polymer binder. Screen-printed then poled, they enable the manufacture of pressure, vibration or impact sensors directly onto flexible substrates, without the assembly constraints of conventional rigid piezoelectric sensors.

Target applications include medical wearables (pulse detection, portable ECG), flexible haptic interfaces and energy harvesting in e-textiles. VFP develops these formulations in partnership with specialist research laboratories. Prototypes are available on request for projects in the R&D phase.

Four technical parameters determine the choice of a conductive ink for a given application. Sheet resistivity (expressed in mΩ/sq or Ω/sq) governs ohmic losses in tracks: the lower the value, the more conductive the ink. Substrate adhesion is measured by the cross-cut test ISO 2409: a poorly formulated ink will delaminate under mechanical stress, compromising circuit reliability.

Flexibility and the curing cycle must be evaluated in conditions representative of the project. Values, test methods and limits applicable to a grade are stated in its technical data sheet.

The choice of a screen printing conductive ink depends on the electrical function, the substrate, the printing process, the maximum curing temperature, flexibility, chemical and thermal resistance and industrialisation constraints.

Silver inks are preferred when high conductivity and low electrical resistance are required. Carbon inks are particularly suited to contacts, resistive elements and applications requiring controlled resistivity. These technologies can be combined in multilayer architectures with dielectric layers. On heat-sensitive substrates, a low temperature conductive ink preserves the film while maintaining electrical performance.

Start with the required function: conductive track, contact or resistive element, interlayer insulation, or piezoelectric function. The grade is then evaluated with the substrate, screen-printing process, target deposit and curing cycle. Technical data sheets for the grades in the range are the starting point for qualification.

Compare the ranges: Silver conductive inks for printed electronic circuits, Conductive and resistive carbon inks for printed electronics, Dielectric inks and varnishes for printed circuits, Printable piezoelectric inks for sensors and smart surfaces.