KU has Developed Extremely Efficient Protective Film for Increasing

Performance and Lifespan of Biodegradable Electronic Components

▲ (From left) Professor Hwang Suk-won (corresponding author), Dr. Han Won-bae, Dr. Ko Gwan-jin, and Kang Hee-seok (master’s student).

KU (President Kim Dong-one) has developed ultrahigh-efficiency protective film materials and processes based on biodegradable and biocompatible materials that are capable of protecting the performance of electronic components and significantly extending their lifespan.

The new coating technology developed by the research group of Professor Hwang Suk-won (KU-KIST Graduate School of Converging Science and Technology) is applicable to biodegradable polymers. In addition, since particles with low water molecule permeability are involved, the highly protective film functions even in a humid environment or in the event of mechanical deformation.

Electronic devices made of biodegradable materials have biocompatible characteristics in that they are dissolved, decomposed, and separated into harmless substances in the body or the environment, thereby changing their physical state and electrical functions. Therefore, the core purpose of the technology is to control the functional lifespan of these materials, and therefore a protective film technology is employed to maintain their functions for a long period of time. However, the existing protective film technology was difficult to apply in relation to electronic devices accompanying a constantly moving human body or operating in various environments because it was unable to control the lifespan of the electronic devices due to the high level of water molecule permeability or the hardness and brittleness of the existing films.

This study overcame the above shortcomings, and it furthermore established a theoretical model that can verify the properties of the new film. In addition, in this study the protective film applied to existing biodegradable materials was implemented via transistors, capacitors, and wireless coils, including light-emitting devices, thereby expanding the scope of practical applications of the lifespan control technology of electronic components and of various biodegradable materials.

Professor Hwang said, “Through this study we developed an ultrahigh-efficiency biodegradable protective film technology that can significantly increase the functions and lifespan of electronic device components.” He added, “As the film can be used as a layer of protection for various electronic devices, we will expand its applicability so that it may be used in our everyday life.”

As the innovation involved in this technology was recognized, the results of the study were published on May 8 (Wed) in Advanced Functional Materials (IF=19.0), an internationally renowned journal.
* Name of journal : Materials and Designs for Extremely Efficient Encapsulation of Soft, Biodegradable Electronics

* 저널명 : Advanced Functional Materials (2024, https://doi.org/10.1002/adfm.202403427)

This study was supported by the Midcareer Research Program and the Electroceuticals Development Program of the National Research Foundation and the ICT Creative Consilience Program of the Institute for Information and Communications Technology Planning and Evaluation.

<Figure 1> 

[Description of Figure 1] Key mechanism and protective properties of the hybrid composite-based antipermeable (HCAP) films.
a. Water diffusion control mechanism dependent on the aspect ratio 𝛼 (𝛼 = particle width/thickness) of the particles in the polymer matrix. b. Relative diffusivity (D/D0) of the hydrophobic polymer (PCL)-based HCAP films with particles of different aspect ratios of 1 (PCL/SP) and 85 (PCL/SF), and mixing volume fractions from 0 to 20%.
c. Water vapor transmission rates (WVTRs) of PCL, PCL/SP20, and PCL/SF20.
d. Protective performance of various HCAP films according to the types of PCL-based particles, measured on the basis of changes in the electrical resistance of magnesium (Mg) in phosphate buffer solution (PBS; pH 7, 37 °C).
e. Simulation of the diffusion of water molecules within PCL/SP20 at day 5 (left) and PCL/SF20 at days 5 (middle) and 40 (right).

<Figure 2> 

[Description of Figure 2]. Mechanical and physical properties of the HCAP films.
a. Photograph and scanning electron microscopy image of the PCL-based HCAP films.
b. Stress-strain curves of the PCL and PCL-based films (red, PCL/SP20; blue, PCL/SF20).
c. Modulus of the PCL-based HCAP films including various shapes of SiO2 depending on the volume fraction.
d. Comparison of mechanical properties of the HCAP films based on various biodegradable polymers.
e. Hydrophobic properties of the HAP films including various particles with different aspect ratios and mixed volume fractions.
f. Electric characteristics of the PCL, PCL/SP20, and PCL/SF20 films depending on the frequency involved.
g. Optical properties of the PCL and PCL-based HCAP films (PCL/SP20 and PCL/SF20).

<Figure 3>

[Description of Figure 3] Application of high-efficiency biodegradable protective films to electronic devices.
a. Photograph of silicon nanomembranes-based n-type metal-oxide-semiconductor field effect transistors (n-MOSFETs) array (left) and degradation properties of devices with PCL/SF20 (right).
b. Complementary metal-oxide-semiconductor (CMOS) inverter (left) with the PLA/SF20 protective film and electrical characteristics of the CMOS inverter (right).
c. Image of a biodegradable capacitor with a cellulose acetate (CA)/SF20 protective film and its electrical characteristics (right).
d. Image of a biodegradable radio frequency (RF) coil with a PLGA/SF20 protective film and its electrical characteristics (right).
e. Image of a wireless power light-emitting diode (LED) system with a PLGA/SF20 protective film and a photograph of the system before its operation in water.
f. A set of images of the water permeability test, showing the ability to suppress the penetration of water to ensure the stable operation of the wireless LED system. The system operated reliably for a period of up to about 40 days.