Problem 134 - Chemistry: An Atoms-Focused Approach

Question

Raincoats "Waterproof" nylon garments have a coating to prevent water from penetrating the hydrophilic fibers. Which functional groups in the nylon molecule make it hydrophilic?

Step-by-Step Solution

Answer

Answer: The amino (NH) and amide (C(O)NH) functional groups in the nylon molecule make it hydrophilic.

Step 1: Understanding basic concepts

Before we dive into the characteristics of nylon, let's first take a moment to understand some key terms: - Hydrophilic: A substance that has an affinity for water or can easily form hydrogen bonds with water is considered hydrophilic. These substances are usually polar in nature. - Functional group: A specific group of atoms within a molecule that is responsible for a characteristic chemical behavior of that molecule.

Step 2: Understanding the structure of nylon

Nylon is a synthetic polymer belonging to the polyamide family. It is formed by the polymerization of dicarboxylic acid and diamines. The general structure of a nylon molecule can be represented as: -(NH-RC(O)-NH-RC(O)-)- where R is a hydrocarbon chain that varies depending on the specific type of nylon.

Step 3: Identifying the functional groups

Now that we have the general structure of nylon, we can identify the functional groups that make it hydrophilic: 1. Amino group (NH) - The nitrogen and hydrogen atoms in the amino group are polar, as nitrogen is more electronegative than hydrogen. Thus, the amino group can form hydrogen bonds with water, making the nylon hydrophilic. 2. Amide group (C(O)NH) - The amide group consists of an oxygen atom double bonded to a carbon atom (C(O)) bonded to a nitrogen atom (NH). The oxygen atom in the amide group is more electronegative than the carbon atom, making the C(O) bond polar. These polar bonds allow nylon to form hydrogen bonds with water, making it hydrophilic. In conclusion, the amino and amide functional groups in the nylon molecule make it hydrophilic.