INTERNATIONAL JOURNAL OF PRECISION ENGINEERING AND MANUFACTURING Vol. 11, No. 6, pp. 987-990 DECEMBER 2010 / 987
DOI: 10.1007/s12541-010-0120-2
1. Introduction
In recent years, soft material and manufacturing processes have
been developed for biomimetic robot and actuators applications.
1,2
Many soft polymers, so call electro-active polymers have been
developed so far including ionic polymer metal composites,
conductive polymers,
3,4
dielectric elastomers and piezoelectric
polymers.
5,6
Cellulose is one of the most naturally abundant
biopolymers. Cellulose has been utilized in many fields due to its
biocompatibility and chirality for the immobilization of proteins,
antibodies as well as the formation of cellulose composites with
synthetic polymers and biopolymers.
7
Recently, cellulose has been
discovered as a smart material that can be used as sensor and
actuator materials.
8
This smart material is termed as electro-active
paper (EAPap).
9
EAPap has many advantages as a smart material in
terms of lightweight, dryness, low cost, biodegradability, large
deformation, low actuation voltage and low power consumption.
10
EAPap actuator is electrically activated due to a combination of ion
migration and piezoelectric effects. Once the piezoelectric effect is
maximized in EAPap, then this material can be used for many
applications such as sensors, microelectro-mechanical systems,
speakers, microphones, transducers, and so on. The improvement
of the piezoelectric effect in the EAPap is strongly associated
with the alignment of cellulose fibers. According to our previous
research, the alignment of cellulose fibers in EAPap has been
achieved by a mechanical stretching that improved its piezoelectric
property.
11,12
In this paper, EAPap was fabricated by an automated process to
realize large-size production and reliable properties of EAPap. The
automated process consists of dissolving, centrifuging, casting,
curing, stretching and drying steps. So far, a fixture has been used
to manually stretch the samples, which holds two ends of the
samples and stretch by turning a screw. However, after stretching
and drying, the shape of the manually stretched samples was turned
out to be convex, which indicated the cellulose fibers were not
aligned parallel to the stretching direction. Thus, for continuous and
parallel stretching of cellulose fibers, a zone stretching method was
innovated.
Evaluation of Cellulose Electro-Active Paper
Made by Tape Casting and Zone Stretching
Methods
Sungryul Yun
1
, Jaehwan Kim
1,#
and Kang-Su Lee
2
1 Center for EAPap Actuator, Department of Mechanical Engineering, Inha University, 253, Yonghyun-dong, Nam-gu, Incheon, Korea, 402-751
2 Korean Register of Shipping, 386-2, 3 Daedeok TBC, Doryong-dong, Yuseong-gu, Daejeon, Korea, 305-340
# Corresponding Author / E-mail: jaehwan@inha.ac.kr, TEL: +82-32-860-7326, FAX: +82-32-832-7325
KEYWORDS: Electro-Active Polymer, Tape Casting, Zone Stretching, Piezoelectricity
Cellulose has been discovered as a smart material that can be used as sensor and actuator material. In this paper,
cellulose smart material termed as electro-active paper (EAPap) is prepared by an automated process that
includes tape casting and zone stretching. To evaluate characteristics of the EAPap, its Young’s modulus and
piezoelectric charge constant are measured depending on the orientation angle, in comparison with the manually
fabricated EAPap results. The zone stretching method can effectively align the cellulose fibers in the EAPap so as
to improve its Young’s modulus as well as piezoelectric charge constant. The 0 degree oriented sample shows its
maximum Young’s modulus and the 45 degree oriented sample exhibits the maximum piezoelectric charge
constant. This 45 degree is associated with its shear piezoelectricity. The actuator performance of EAPap is
evaluated by measuring its bending displacement depending on the orientation angle and the excitation voltage.
The 45 degree oriented sample exhibits the maximum bending displacement. Details of the material preparation,
the automation process, characterization and the actuator performance are addressed. This automated process
that includes tape casting and zone stretching is suitable for mass production of the EAPap.
Manuscript received: July 19, 2010 / Accepted: August 9, 2010
© KSPE and Springer 2010