ArticlePDF Available

Optimization of Inkjet Printing of Patch Antennas on Low-Cost Fibrous Substrates

January 2014
IEEE Antennas and Wireless Propagation Letters 13:915-918

DOI:10.1109/LAWP.2014.2322572

Authors:

Hossein Saghlatoon

University of Alberta

Lauri Sydänheimo

Tampere University

Manos Tentzeris

Georgia Institute of Technology

In this letter, the inkjet-printing procedure is used to implement microwave circuits on low-cost fibrous substrate, cardboard. As a first step for environmentally friendly electronics applications, the high-frequency properties of the cardboard substrate are extracted using the two-transmission-line method and dielectric probe measurement. To provide an accurate model for the inkjet-printed conductors, the conductivity and thickness of the printed silver traces are analyzed. The surface of the substrate is pretreated using a dielectric ink to reduce the penetration of the conductor ink into the fibrous substrate and to diminish the conductor loss at high frequencies. As a technology demonstrator, a patch antenna is printed on a cardboard substrate, and the simulation and measurement results are compared to study the reliability of the obtained parameters. After initial experimental verification, simulation models were fine-tuned in order to provide a predictive method for design and fabrication of low-cost RF circuits. The achieved model can be used to design and fabricate low-cost RF structures on fibrous environmentally friendly substrates .

Implemented microstrip lines on cardboard.

…

Measured properties of cardboard. (a) Relative permittivity. (b) Loss tangent.

…

Fabricated inkjet microstrip lines on cardboard.

…

Measured thickness of the ink (a) after treatment and (b) before treatment.

…

Scanned surface of cardboard using optical profilometer. (a) Before treatment. (b) After treatment.

…

Figures - uploaded by Manos Tentzeris

Content may be subject to copyright.

Content uploaded by Manos Tentzeris

Content may be subject to copyright.

IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS, VOL. 13, 2014 915

Optimization of Inkjet Printing of Patch Antennas on

Low-Cost Fibrous Substrates

Hossein Saghlatoon, Lauri Sydänheimo, Member, IEEE, Leena Ukkonen,Member,IEEE,and

Manos Tentzeris, Fellow, IEEE

Abstract—In this letter, the inkjet-printing procedure is used

to implement microwave circuits on low-cost ﬁbrous substrate,

cardboard. As a ﬁrst step for environmentally friendly electronics

applications, the high-frequency properties of the cardboard sub-

strate are extracted using the two-transmission-line method and

dielectric probe measurement. To provide an accurate model for

the inkjet-printed conductors, the conductivity and thicknessof

the printed silver traces are analyzed. The surface of the substrate

is pretreated using a dielectric ink to reduce the penetration of

the conductor ink into the ﬁbrous substrate and to diminish the

conductor loss at high frequencies. As a technology demonstrator,

a patch antenna is printed on a cardboard substrate, and the

simulation and measurement results are compared to study the

reliability of the obtained parameters. After initial experimental

veriﬁcation, simulation models were ﬁne-tuned in order to provide

a predictive method for design and fabrication of low-cost RF

circuits. The achieved model can be used to design and fabri-

cate low-cost RF structures on ﬁbrous environmentally friendly

substrates.

Index Terms—Dielectric characterization, green electronics,

inkjet printing, low-cost substrate, paper RF, patch antenna, silver

ink, surface treatment, two transmission lines method.

I. INTRODUCTION

AS AN organic substrate, paper has a great potential for

the realization of environmentally friendly and recyclable

electronics [1], [2]. It is tempting to use paper as a substrate

for electronic circuits because it is ultra-low-cost, recyclable,

available everywhere, and compatible with printing [3]. Addi-

tive printing technologies, such as inkjet printing, feature the

capability to increase the fabrication speed and enhance the pro-

duction versatility, both features that are critical for mass pro-

duction. Moreover, inkjet printing has been an enabling tech-

nology to print electronics on unconventional substrates such

as wood, ceramic, and paper [3]–[5]. The electrical properties of

the low-cost ﬁbrous types of paper, such as cardboard, should be

characterized, especially in microwave frequencies because the

RF properties of different paper materials are not identical [3].

In addition, it is challenging to effectively fabricate circuits on

Manuscript received December 13, 2013; revised February 20, 2014 and

April 04, 2014; accepted April 17, 2014. Date of publication May 08, 2014;

date of current version May 22, 2014.

H. Saghlatoon, L. Sydänheimo, and L. Ukkonen are with the TampereUniver-

sity of Technology, 33720 Tampere, Finland (e-mail: hossein.saghlatoon@tut.ﬁ;

lauri.sydanheimo@tut.ﬁ; leena.ukkonen@tut.ﬁ).

M. M. Tentzeris is with the Georgia Institute of Technology, Atlanta, GA

30332-250 USA (e-mail: etentze@ece.gatech.edu).

Color versions of one or more of the ﬁgures in this letter are available online

at http://ieeexplore.ieee.org.

Digital Object Identiﬁer 10.1109/LAWP.2014.2322572

ﬁbrous substrates using inkjet printing because the printed ink

penetrates into the substrate and reduces the conductivity and

quality of the printed pattern [6].

In this letter, one typical cardboard paper material is used

as the substrate and silver nanoparticle ink as the conductor.

The rest of this letter is organized as follows. In Section II, the

speciﬁcs of the cardboard electrical characterization technique

are discussed. Then, the measurement results for the conduc-

tivity, thickness, and surface roughness of inkjet-printed silver

traces before and after treatment of the substrate are proposed

according to Section III. Section IV discusses the design of a

patch antenna according the obtained parameters, and the effect

of inaccuracies in the fabrication and measurement procedures.

Finally, conclusions are presented in Section V.

II. RF CHARACTERIZATION OF THE CARDBOARD

To enable the effective implementation of efﬁcient microwave

structures on a cardboard substrate, its RF properties have to be

measured and analyzed. There are different ways to characterize

an unknown substrate such as split-cylinder resonator, ring

resonator, and other high- structures [7], [8]. One of the most

accurate methods is the two-transmission-line method. In this

method, two identical microstrip lines with different lengths are

implemented on the substrate. The effective permittivity

of the substrate can be obtained from the phase difference of the

signals, and the loss tangent is acquired from the insertion loss. It

is not necessary to de-embed the effect of SMA connectors and

junctions because all the calculations are based on the transmis-

sion-line length difference effectively removing these parasitic

effects [8], [9]. Using (1) and (2) the effective permittivity and

total loss can be calculated, respectively

(1)

(2)

where is the free-space speed of light, is the phase dif-

ference of the output signals for the long and the short lengths,

is the frequency, and is the length difference of the two

microstrip lines [8], [10].

By knowing the total loss and conductor loss, the dielec-

tric loss and then the loss tangent can be determined. The total

loss is the summation of dielectric loss, conductor loss, and ra-

diation loss. The radiation loss is very low and can be neglected

from the calculations because the lengths of the lines are rela-

tively small. In this case, to have a high efﬁcient traveling wave

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916 IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS, VOL. 13, 2014

Fig. 1. Implemented microstrip lines on cardboard.

antenna, the length of the lines should be to . The con-

ductor loss is dependent on the physical properties of the con-

ductor, such as the conductivity and the width of the line. If the

properties of the conductor are known, the conductor loss is ap-

parent. The conductor loss of a certain transmission line can be

obtained using

(3)

(4)

where is the angular frequency, is the conductivity of the

conductor, is the characteristic impedance of the line, and

is the width of the microstrip line. Moreover, the loss tangent

can be obtained using (5) which is valid for microstrip lines [10]

(5)

where is the dielectric loss, is the relative permittivity

of the substrate, is the effective relative permittivity of the

substrate, and is the phase constant in free space [10].

For the characterization of the highly ﬁbrous cardboard (Stora

Enso packaging thin paper), three microstrip lines with 15-, 10-,

and 5-cm lengths were realized on its surface utilizing a 50-

m-thick copper tape with bulk conductivity of S/m, ter-

minated in 50- SMA conductors, and having the same width of

2 mm for a characteristic impedance of 50 , as shown in Fig. 1.

Thelongestlineisalmost ; hence, the assumption for low

radiation loss is acceptable. For higher measurement reliability,

-parameters for the three different lengths were compared one

by one utilizing an Agilent PNA E8358A two-port vector net-

work analyzer (VNA) between 500 MHz and 3 GHz. To realize

the accuracy of this method, the relative permittivity and loss

tangent were measured using Agilent 85070 Dielectric Probe

Kit in the same frequency interval. The results for the average

permittivity and loss tangent of the substrate using these two

methods are depicted in Fig. 2. The results are in a sufﬁciently

good agreement. Depending on the density and water content of

cardboard, its permittivity can vary between 1.2 and 1.5 [11].

III. CHARACTERIZING THE PRINTED SILVER INK

The next important step for the inkjet printing of RF struc-

tures on cardboard is the characterization of the conductivity

and the realized thickness of the printed conductive traces.

NPS-JL silver ink with 55.5wt% metal content was used to

print using Dimatix DMP-2831 inkjet material printer. The

volume and diameter of each droplet was 10 pL and 140 m,

Fig. 2. Measured properties of cardboard. (a) Relative permittivity. (b) Loss

tangent.

Fig. 3. Fabricated inkjet microstrip lines on cardboard.

respectively. To optimize the conductivity value, a sintering

process at 150 for 1 h with air circulation was applied, and

each RF pattern was printed [12]. For appropriate conductivity,

each pattern was printed in four cycles. In each cycle, two

layers of silver ink were printed and sintered, so at the end there

were eight layers of silver ink with the total thickness of 3 m

on cardboard.

Following this process, three microstrip lines with different

lengths were printed on cardboard as shown in Fig. 3. The di-

mensions of these lines are identical to the copper tape versions

for the purpose of easier comparison. In this case, the dielectric

loss is known, and by measuring the total loss, the conductor

loss can be obtained. The acquired value for the conductivity of

these structures is S/m.

Considering the cardboard substrate, there are numerous rea-

sons that led to a reduced value of conductivity compared to the

maximum achievable value S/m presented by the

manufacturer. These include the lower realized conductor thick-

ness compared to the skin depth and the high surface roughness.

The thickness of the printed silver ink on cardboard was mea-

sured using an optical microscope. The ink penetrates into the

cardboard due to its highly ﬁbrous nature [6]. By penetration

of the ink into the ﬁbrous substrate, the conductivity diminishes

because the printed silver nanoparticles cannot make a uniform

conductor. In addition, cardboard is not a good thermal con-

ductor; hence, in the sintering process, the printed silver ink is

not cured properly. Therefore, there is a demand to make the

surface smooth and ink proof. It can be easily seen in Fig. 4

that without a surface treatment approach, the ink penetration

into the substrate is around 55 m. Usually, different dielec-

tric inks are utilized to treat the surface [13], [14]. We used

a conventional primer (composed of tetrahydrofurfuryl acry-

late, ethoxylated trimethylolpropane triacrylate, 2-hydroxy-2-

methyl-1-phenyl-propan-1-one, and bis-phenylphosphineoxide

SAGHLATOON et al.: OPTIMIZATION OF INKJET PRINTING OF PATCH ANTENNAS ON LOW-COST FIBROUS SUBSTRATES917

Fig. 4. Measured thickness of the ink (a) after treatment and (b) before

treatment.

Fig. 5. Scanned surface of cardboard using optical proﬁlometer. (a) Before

treatment. (b) After treatment.

[6]) to prepare a smooth surface for silver ink [6]. For this pur-

pose, four layers of primer with 1016 dpi resolution were printed

separately on the rough surface of cardboard. After the printed

deposition of each layer, it was cured using ultraviolet light

(UV) for 15 min, and then 1 h at 150 in an oven. Afterwards,

silver ink was inkjet-printed on the treated surface utilizing the

conventional sintering approach.

The surface roughness of the printed silver ink on the treated

and untreated cardboard was scanned using an optical pro-

ﬁlometer with results shown in Fig. 5. As can be deduced,

the peak-to-valley distance is around 39 m before treatment,

whichisimprovedto11.5 m after treatment. Moreover,

the mean roughness and root mean squared roughness are

improved from 1.68 and 2.13 m before treatment to 1.3 and

1.62 m after treatment, respectively. After the preparation

of the smooth and ink-proof surface, the same microstrip

lines were printed to analyze the new value of conductivity,

which was found to be almost double S/m .The

other important parameter for the printed silver ink traces for

high-frequency designs is the conductor thickness uniformity.

The cross section of the treated cardboard with printed silver

ink is shown in Fig. 4. As can be seen, the thickness is almost

uniform in the whole printed area and equal to 3 m.

Fig. 6. Conﬁguration of the inkjet-printed patch antenna on cardboard.

Fig. 7. Simulation and measurement results for the proposed antenna. (a) Ra-

diation efﬁciency. (b) Radiation gain. (c) Return loss.

TAB L E I

OBTAINED VALUES FOR DIFFERENT PARAMETERS OF CARDBOARD

AND SILVER INK

IV. IMPLEMENTATION OF THE 2.45 GHZPATC H ANTENNA

As a proof of concept and without loss of generality, a mi-

crostrip patch antenna for 2.45 GHz with inset feeding was de-

signed for the acquired properties of the cardboard and of the

silver ink traces presented in Table I. The antenna is designed to

operate in the excitation mode, and its dimensions are

shown in Fig. 6.

This conﬁguration was simulated using the 3-D full-wave

electromagnetic simulator Ansys HFSS based on ﬁnite element

method, while the inkjet-printed prototype was measured using

the near-ﬁeld measurement equipment Satimo Starlab. The sim-

ulation and measurement results for the radiation gain, radiation

efﬁciency, and return loss are shown in Fig. 7. As can be seen,

there are slight discrepancies between the simulation and mea-

surement results. We believe these discrepancies arise due to

layer-to-layer alignment error and printer tolerances m .

However, it can be observed that this phenomenon increases the

918 IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS, VOL. 13, 2014

Fig. 8. (a) Current distribution in the patch antenna at 2.45 GHz. (b) Misalign-

ment of the printed layers.

Fig. 9. Simulation and measurement results with the optimized model. (a) Ra-

diation efﬁciency. (b) Radiation gain. (c) Return loss.

losses in the radiating edges of the patch antenna and of the

feeding line.

The results for the measured misalignment of different layers

using an optical microscope and for the simulated of the cur-

rent distribution magnitude are shown in Fig. 8. As can be seen

in Fig. 8(b), the misalignments of different layers are approxi-

mately in the range of 130 m and shown with the red shift. To

compensate for the effect of misaligned layers in the simulation

model, the conductivity of the radiating edges and of the feeding

line edges is reduced. The width and conductivity of the added

part in the simulations is 130 mand S/m. The afore-

mentioned two-transmission-line method was used to measure

the conductivity of the misaligned part.

Fig. 9 depicts the simulation results for the radiation efﬁ-

ciency, radiation gain, and return loss for the new corrected

model. With this model, the matching between the simulated

and measured efﬁciency is improved by 1.5%, and the gain by

1 dB. Another potential source of measurement error is the inac-

curacy of the near-ﬁeld measurement device, which is dB

for the peak gain at 1880 MHz. Compared to the simulation

model, the roughness of the printed structure is another source

of error that will be modeled in the further studies.

V. C ONCLUSION

We have presented a novel method for the optimization of

inkjet printing of RF structures on ﬁbrous substrates. As a proof

of concept, the properties of a typically highly ﬁbrous card-

board substrate as well as of the inkjet-printed silver traces are

accurately characterized up to 3 GHz. A smoothness/substrate

hermeticity enhancing approach for the cardboard is presented,

and numerous uncertainties of inkjet printing approach are mod-

eled. The acquired values for the permittivity and loss tangent

of the cardboard, as well as the thickness and the conductivity

values for the printed silver traces are 1.78, 0.025, 3 m, and

S/m, respectively. Based on the developed method, a

patch antenna is simulated, fabricated with inkjet printing on

cardboard, and then measured. Finally, the simulation and mea-

surement results were compared, and acceptable agreement is

achieved. It can be concluded that the optimized model for card-

board and silver ink can be used in the fabrication and optimiza-

tion of RF structures on ultra-low-cost highly ﬁbrous substrates,

such as cardboard.

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Chapter

Apr 2022

Fifth Generation (5G) communication tools are extremely important for the modern society, especially when more and more of our activities are organized in such a way as to be carried out rapidly and more efficiently even if they are to take place from a distance. There are many possibilities, using different advanced materials, to fulfill the high demand of the antennas with different functionalities. Investigation on the characteristics of the material used in this application is a starting point to be really able to manage in a proper way the performance of the antenna. Understanding the most important characteristics allows designing material with low or even controlled dispersion that intrinsically will increase the performance of the antenna. The present chapter reports some fundamental elements belonging to such a wide-ranging topics used up to date, even if it does not target to fully cover all features about any material used in this field. The aim of the present chapter is to present different challenges in designing 5G communication tools, starting from the selection of the appropriate material up to their production methods. It also includes some aspects related to the multidisciplinary face of such research developments in order to highlight the necessity of the participation of many scientific figures to attain enhanced characteristics of the future communication systems. Additionally, an insight into future communication networks from material point of view is provided. Some of the major challenges in THz communications, body implant antennas and wearable antennas are discussed also. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.

Design of Conformal Antenna Arrays for Wide Angle Scanning

Chapter

Apr 2022

There has been a steadily increasing demand for higher bandwidths in modern communication systems, which in turn has led these systems to gravitate to higher frequencies, e.g., the Ka-band, for the fifth generation (5G) systems. Beam scanning is an essential feature of the 5G systems since it helps to improve the power efficiency as well as wide-angle scan capability. Typically, phased array antennas are widely used for the purpose of beam scanning; however, the phased arrays suffer from the disadvantages of design complexity, large bulk, appetite for high power consumption, and requirement for a large-size real estate to accommodate them, especially when their gain requirement is high. The design process for the array becomes even more complex when the array needs to be mounted conformally to the platform, and multiple approaches for alternate designs for such antenna arrays have been proposed in the literature. In this chapter, first, we begin by discussing the Gradient-index lens (GRIN)—specifically the Luneburg lens—which provides a good alternative to the conformal phased array. We show that the Luneburg lens is useful for multi-beam, wide-angle, low-cost, and wideband communication applications. Next, we discuss a general-purpose technique to design conformal antenna arrays with ultra-wide-angle scan capabilities. All the designs proposed herein provide wide-angle beam-scanning, with low scan-loss, and are good candidates for 5G communication systems.

Inkjet-printed planar antenna for a wireless sensor on paper operating at Wi-Fi frequency

Conference Paper

Full-text available

Jul 2012

Organic substrates is one of the leading solutions to realize ultra-low-cost and “green” wireless sensor applications. Inkjet printing on paper would be particularly economically appealing if commercial antennas could be replaced with printed antennas with similar performance. This paper presents the replacement of an inkjet-printed, planar, inverted-F antenna (PIFA) for a conventional commercially available, three dimensional (3D) monopole used in a Smart Wireless Integrated Module (SWIM). Both the sensor layout and PIFA antenna are inkjet-printed on paper substrate, in a first successful step towards the implementation of a fully operational, fully planar wireless sensor on paper at Wi-Fi frequency (2.4 GHz).

Embedding Ink-Jet Printed Antennas into Plywood Structures for Identification and Sensing

Conference Paper

Full-text available

Nov 2012

The embedding of radio frequency identification (RFID) tags into plywood boards will enable the identification and tracking of individual plywood boards and end products of plywood. Even more benefits can be achieved by adding sensing functions into these tags. We present tags that are embeddable inside plywood by direct inkjet-printing on pure birch veneer. The use of passive UHF RFID technology in the plywood industry is discussed, two tag antenna designs for plywood are presented and the tag fabrication procedures are described. Furthermore, tag performance measurement results from various setups are presented to verify the concept of embedding RFID and sensor antennas into plywood structures. Measurements show that tags printed on veneer and embedded inside 2 mm thick plywood board exhibited theoretical read ranges from 7.9 meters to 10.3 meters. The read ranges obtained meet the demands of the plywood industry and offer reliable identification even in challenging environments.

ChemInform Abstract: “Green” Electronics: Biodegradable and Biocompatible Materials and Devices for Sustainable Future

Article

Full-text available

Oct 2013
CHEM SOC REV

Mihai Irimia-Vladu

"Green" electronics represents not only a novel scientific term but also an emerging area of research aimed at identifying compounds of natural origin and establishing economically efficient routes for the production of synthetic materials that have applicability in environmentally safe (biodegradable) and/or biocompatible devices. The ultimate goal of this research is to create paths for the production of human- and environmentally friendly electronics in general and the integration of such electronic circuits with living tissue in particular. Researching into the emerging class of "green" electronics may help fulfill not only the original promise of organic electronics that is to deliver low-cost and energy efficient materials and devices but also achieve unimaginable functionalities for electronics, for example benign integration into life and environment. This Review will highlight recent research advancements in this emerging group of materials and their integration in unconventional organic electronic devices.

Microwave Engineering

Article

Jan 1998

David Pozar

"Green'' electronics: biodegradable and biocompatible materials and devices for sustainable future (vol 43, pg 588, 2014)

Article

Jan 2014

Mihai Irimia-Vladu

Microwave Engineering

Book

May 2004

David Pozar

Focusing on the design of microwave circuits and components, this valuable reference offers professionals and students an introduction to the fundamental concepts necessary for real world design. The author successfully introduces Maxwell's equations, wave propagation, network analysis, and design principles as applied to modern microwave engineering. A considerable amount of material in this book is related to the design of specific microwave circuits and components, for both practical and motivational value. It also presents the analysis and logic behind these designs so that the reader can see and understand the process of applying the fundamental concepts to arrive at useful results. The derivations are well laid out and the majority of each chapter's formulas are displayed in a nice tabular format every few pages. This Third Edition offers greatly expanded coverage with new material on: Noise; Nonlinear effects; RF MEMs; transistor power amplifiers; FET mixers; oscillator phase noise; transistor oscillators and frequency multiplier.

inkjet-Printable UHF RFID Tag Antenna on a Flexible Ceramic- Polymer Composite Substrate

Article

Jun 2012

The utilization of inkjet-printing technique to develop a printable UHF RFID tag antenna on flexible ceramic-polymer composite material is demonstrated. The substrate material is fabricated using high permittivity Barium Titanate (BaTiO3) ceramic powder mixed with polydimethylsiloxane (PDMS) polymer. A UHF RFID tag antenna is inkjet-printed using silver nano-particle to exploit the potential advantages of high dielectric flexible composite material when used as a tag substrate. Our preliminary results yielded a small flexible UHF RFID tag antenna with read range comparable to commercially available tag antennas.

Substrate pre-treatment of flexible material for printed electronics with carbon nanotube based ink

Article

Feb 2011

In this work, an innovative solution was developed in order to make paper-based material, used traditionally in the packaging and labelling industries, compatible with the printing of functional conductive inks. In order to avoid the deterioration of the ink functionalities due to different paper properties, a UV-curing inkjettable primer layer was developed. This pre-treatment enables homogeneous surface properties such as smoothness, absorption capacity and surface energy to be obtained, for almost all the examined substrates. To confirm the positive impact of such pre-treatment, conductivity has been measured when using a new conductive ink, combining the processability of the PEDOT–PSS conductive polymer with the high electrical properties of carbon nanotubes (CNTs). Significant improvement has been measured for all paper materials and similar conductivity (close to reference PET film) has been obtained whatever the substrate involved. This pre-treatment now makes it possible to consider paper-based material as a potential substrate for printed electronics. In this case, the substrate adaptation technique offers an innovative solution to produce low-cost and flexible electronics.

A universally applicable method for fabricating superhydrophobic polymer surfaces

Article

Aug 2012
COLLOID SURFACE A

h i g h l i g h t s A simple method to produce super-hydrophobic surfaces in polymers was developed. This method was demonstrated for PMMA, PC and COC polymers. Surface morphology and wetting were studied as a function of O2 plasma time. The fabricated superhydrophobic surfaces were stable up to 90 days. g r a p h i c a l a b s t r a c t a b s t r a c t The modification of polymer surfaces to manipulate their wetting properties is of great technological importance. It is well known that surface chemistry and topography jointly determine the nature of wetting on a surface. In this study, we show a cheap and effective process universally applicable to fabricate superhydrophobic surfaces on various polymers. The process combines sanding and reactive ion etching treatment of the polymer surface to generate respective micro and nanoscale surface roughness, which is followed by subsequent coating of a fluorinated silane molecule to modify the surface chemistry. A 5 min reactive ion etching treatment after sanding is sufficient to achieve nanoscale roughness required for superhydrophobic surfaces. The polymer surfaces so produced retain their superhydrophobicity for more than 90 days, demonstrating the stability of the micro and nanoscale surface roughness and the hydrophobic surface coating. Similar results are obtained with different polymers such as poly(methyl methacrylate) (PMMA), polycarbonate (PC) and cyclo-olefin copolymer (COC), indicating that the process can be applied for creating superhydrophobic surfaces on general polymer substrates.

A multilayer coated fiber-based substrate suitable for printed functionality

Article

Aug 2009
ORG ELECTRON

A recyclable multilayer coated fiber-based substrate combining sufficient barrier and printability properties for printed functional devices was developed using reel-to-reel techniques. The substrate consists of a mineral pigment layer coated on top of a barrier latex layer. The pigment layer allows controlled absorption of ink solvents. By adjusting the thickness and porosity of the top coating the printability can be tuned for various functional inks. As a proof of concept a hygroscopic insulator field effect transistor (HIFET) was successfully printed on the multilayer-coated paper.