In this blog post, we’ll explore the basic concepts and various properties of polymers, as well as their potential applications, with a focus on LCDs.
Concepts and Characteristics of Polymers
Polymers are important materials used in every aspect of our lives, but despite their significance, they remain a somewhat unfamiliar field to the general public. Unlike the patent dispute between Samsung and Apple, which garnered global attention, the technology dispute between Kolon and DuPont over aramid fibers was relatively less well-known. At the time, Kolon suffered a major setback after receiving a significant ruling that included massive damages and restrictions on product sales. Aramid fiber is a representative polymer material that, while as thin as a thread, possesses exceptional strength when woven into fabric; it is widely used in various high-tech industries, including the defense and aerospace sectors. Understanding the properties of polymers naturally explains how such a thin fiber can possess strength rivaling that of steel.
Polymers are one of the key areas in organic chemistry, which studies the structure and properties of organic compounds centered on carbon. Small molecules—composed primarily of carbon and hydrogen, with atoms such as oxygen and nitrogen bonded to them—are linked together through a series of chemical reactions, ranging from hundreds to hundreds of thousands or more, to form massive molecules with repeating structures. These massive molecules are called polymers. The basic units that form polymers are called monomers, and the giant molecules created by the repetitive linking of monomers are called polymers.
At first glance, one might wonder how monomers—which are simply linked together—can possess entirely different properties. To understand this, it helps to consider a simple example involving probability. If you flip a coin twice, there are 2², or 4, possible outcomes. However, if you flip it ten times, the number of possible outcomes becomes 2¹⁰, or 1,024. Even a slight increase in the number of flips causes the number of possible combinations to increase exponentially. The structure of polymers is similar.
In reality, polymers have far more variables than coin flips. Monomers can be linked in a straight chain, form branches, or create various three-dimensional structures, and the patterns of repetition are also extremely diverse. Above all, because there are so many different types of monomers, the number of possible polymers is virtually infinite. Such diverse structures lead to different physical properties, and thanks to these characteristics, polymers are replacing a wide range of traditional materials.
The Principle of Polymers Used in LCDs
One of the most representative applications is the LCD (Liquid Crystal Display). However, in today’s display industry, various display technologies—such as OLED (Organic Light-Emitting Diode)—are also widely used alongside LCDs. While aramid fibers are polymers that utilize exceptional mechanical strength, the various materials that make up an LCD employ a range of polymer materials that interact with light. By appropriately designing the structure of a polymer, it is possible to achieve properties that respond to light of specific wavelengths, and these properties play a crucial role in the advancement of display technology.
One of the key concepts for achieving these properties is the conjugated structure. While a precise understanding of this requires knowledge of atomic structure, orbitals, and chemical bonds, we will focus here only on the core concepts.
A conjugated structure refers to a structure in which double bonds and single bonds alternate repeatedly. In typical covalent bonds, electrons are relatively strongly bound to specific bonds, but in a conjugated structure, electrons can spread more widely across the entire molecule. This change in electron distribution significantly alters the molecule’s optical and electronic properties and serves as the core principle for creating various functional polymers.
When a conjugated structure forms, electrons are not confined to specific atoms but can move relatively freely throughout the entire molecule. This characteristic also affects interactions with light, resulting in various optical properties. To put it simply, this can be likened to a student who focuses solely on one teacher during private tutoring but has their attention分散 across multiple subjects and diverse environments at school. Similarly, electrons are distributed throughout the entire molecule rather than remaining in a specific location.
The Future Shaped by Polymers
LCDs, which utilize this principle, display images through the combined operation of various components, including liquid crystals, polarizing filters, color filters, and thin-film transistors (TFTs). Polymers play a crucial role in these various components and materials and have greatly contributed to the evolution of LCDs into thin and lightweight displays. While CRT (Cathode Ray Tube) displays were bulky and heavy due to their tube structure, LCDs made it possible to create much thinner and lighter products. Furthermore, because they enable flat screens, the screen distortion issues common in traditional CRTs have been significantly improved.
In this way, polymers have established themselves as core materials across various industries, resolving many inconveniences in our daily lives based on their nearly limitless structural possibilities and diverse physical properties. The importance of polymers continues to grow not only in displays but across all advanced industries, including semiconductors, electric vehicles, medical devices, aerospace, and eco-friendly materials; based on this, research to develop new functional materials is also actively underway. Although South Korea was once a latecomer in the field of polymers, it has now secured global competitiveness in various sectors, including display materials, rechargeable battery materials, and semiconductor materials. If continuous research, development, and investment continue, the polymer industry will play an even more crucial role as a key sector driving the advancement of future cutting-edge technologies.
