Preface

The interest in flexible electronics is on the rise as it brings an added functionality and es‐ thetic value in the unconventional interfaces, such as biomonitoring systems, wearables, flexible textiles, paper-based technologies, and many other curves of soft schemes, for which traditional electronics are not suitable. The demand in new flexible platforms turns to a pur‐ suit for functional materials and technologies commonly compatible with a low tempera‐ ture, high-throughput processing, and novel methods for device integration. New device design leads to an immense field from fundamental research to the new technologies and engineering methods bringing advanced functionality. A wide range of functional materials involving nanoparticles, composites, semiconductor and metallic nanowires, carbon nano‐ materials, polymers, conductive inks, and different hybrid structures are particularly inter‐ esting. Printing technologies have been demonstrated to be highly efficient and compatible with many flexible substrates; furthermore, surface preparation methods play an important role for the fabrication of electronic devices. This book brings a comprehensive overview on the most important technology development in the field of flexible electronics. The interest in flexible electronics is on rise as it brings an added functionality and thetic value in the unconventional interfaces, such as biomonitoring systems, suitable. in platforms suit for functional materials and technologies commonly compatible with a low ture, high-throughput processing, and novel methods for device integration. New design leads to an immense field from fundamental research to the new technologies involving nanoparticles, composites, semiconductor and metallic nanowires, carbon materials, polymers, conductive inks, and different structures are particularly esting. Printing have been demonstrated to be flexible substrates; furthermore, surface preparation play an

> **Simas Rackauskas** University of Turin Turin, Italy

**Chapter 1**

**Provisional chapter**

**Surface Modification of Polyimide Films for Inkjet-**

**Surface Modification of Polyimide Films for** 

**Inkjet-Printing of Flexible Electronic Devices**

DOI: 10.5772/intechopen.76450

Kapton polyimide films are one of the most commonly used flexible and robust substrates for flexible electronic devices due to their excellent thermal, chemical, mechanical, and electrical properties. However, such films feature an inert and highly hydrophobic surface that inhibits the deposition of functional materials with water-based fluids (solutions, suspensions, inkjet inks, *etc*.), which raise the need for their surface modification to reduce their inherent surface inertness and/or hydrophobicity in order to allow for the fabrication of electronic devices on the substrates. Traditional Kapton surface modification approaches use harsh conditions that not only cause environmental and safety problems but also compromise the structural integrity and the properties of the substrates. This chapter focuses on two recently-developed mild and environmentally friendly wet chemical approaches for surface modification of Kapton HN films. Unlike the traditional methods that target the polyimide matrix of Kapton films, these two methods target the slip additive embedded in the polyimide matrix. The surface modified Kapton films resulted from these two methods allowed for not only great printability of both waterand organic solvent-based inks (thus facilitating the full-inkjet-printing of entire flexible electronic devices) but also strong adhesion between the inkjet-printed traces and the

**Keywords:** surface modification, Kapton, polyimide, flexible electronic devices, sensors,

Kapton HN films, which are well known to be made of polyimide polymer, are one of the most commonly used substrates for flexible electronics due to their excellent physical and

> © 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use,

distribution, and reproduction in any medium, provided the original work is properly cited.

**Printing of Flexible Electronic Devices**

Yunnan Fang and Manos M. Tentzeris

Yunnan Fang and Manos M. Tentzeris

http://dx.doi.org/10.5772/intechopen.76450

**Abstract**

substrate films.

inkjet-printing

**1. Introduction**

Additional information is available at the end of the chapter

Additional information is available at the end of the chapter

#### **Surface Modification of Polyimide Films for Inkjet-Printing of Flexible Electronic Devices Surface Modification of Polyimide Films for Inkjet-Printing of Flexible Electronic Devices**

DOI: 10.5772/intechopen.76450

Yunnan Fang and Manos M. Tentzeris Yunnan Fang and Manos M. Tentzeris

Additional information is available at the end of the chapter Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.76450

#### **Abstract**

Kapton polyimide films are one of the most commonly used flexible and robust substrates for flexible electronic devices due to their excellent thermal, chemical, mechanical, and electrical properties. However, such films feature an inert and highly hydrophobic surface that inhibits the deposition of functional materials with water-based fluids (solutions, suspensions, inkjet inks, *etc*.), which raise the need for their surface modification to reduce their inherent surface inertness and/or hydrophobicity in order to allow for the fabrication of electronic devices on the substrates. Traditional Kapton surface modification approaches use harsh conditions that not only cause environmental and safety problems but also compromise the structural integrity and the properties of the substrates. This chapter focuses on two recently-developed mild and environmentally friendly wet chemical approaches for surface modification of Kapton HN films. Unlike the traditional methods that target the polyimide matrix of Kapton films, these two methods target the slip additive embedded in the polyimide matrix. The surface modified Kapton films resulted from these two methods allowed for not only great printability of both waterand organic solvent-based inks (thus facilitating the full-inkjet-printing of entire flexible electronic devices) but also strong adhesion between the inkjet-printed traces and the substrate films. printability

**Keywords:** surface modification, Kapton, polyimide, flexible electronic devices, sensors, inkjet-printing
