Читать книгу Materials for Biomedical Engineering - Mohamed N. Rahaman - Страница 64

Although considerably weaker than the primary bonds (Table 2.2), secondary bonds still have a significant effect on the properties of some materials. Secondary bonds are typically intermolecular bonds. Intermolecular bonding between neighboring chains, for example, is responsible for polyethylene and many other polymers existing as a solid at room temperature. Without intermolecular bonding between its polar molecules, water would boil at approximately −80 °C instead of existing as a liquid at room temperature. Proteins are the most versatile macromolecules in living organisms and they serve crucial functions in essentially all biological processes. As described in Section 2.6, intermolecular bonding in these macromolecules controls the shape (conformation) that these macromolecules take up and, thus, their functions. Secondary bonds are often divided into two main types: van der Waals bonds and hydrogen bonds.