The phenomenon of milk coating on the mouth, often described as a milky film or residue lingering after drinking milk, is primarily due to the unique composition and properties of milk. Milk is a complex mixture of water, proteins (like casein and whey), fats, lactose, minerals, and vitamins. When milk is consumed, its fatty content and proteins can interact with the saliva in the mouth, creating a temporary coating. This sensation is more pronounced with whole milk due to its higher fat content. Some individuals may also experience this effect more intensely if they have a sensitivity to certain components in milk, such as lactose or specific proteins. Additionally, the temperature at which milk is consumed can affect the perception of the coating; cold milk tends to produce a more noticeable effect. To minimize this sensation, one can rinse the mouth with water after consuming milk or choose low-fat or lactose-free alternatives.

A crystalline cellulose chain refers to the highly ordered structure of cellulose, which is the most abundant organic polymer on Earth, primarily found in plant cell walls. Cellulose is composed of β(1→4) linked D-glucose units, which form long linear chains. These chains pack closely together via hydrogen bonds and Van der Waals forces, creating a rigid, crystalline structure. This crystalline arrangement is crucial for the mechanical strength and structural integrity of plant cell walls. It also makes cellulose resistant to water and enzymatic degradation, challenging its use in biofuel production. However, its crystallinity is what researchers target to modify or degrade for various applications, including the production of biofuels, textiles, and paper. Understanding the structure and properties of crystalline cellulose is essential for advancements in material science, bioengineering, and environmental sustainability.

Acrylic yarn is made from synthetic polymer called acrylonitrile, which is derived from natural gas and petroleum. The process begins with the polymerization of acrylonitrile with various other chemicals to create a long chain polymer. This polymer is then dissolved in a solvent to form a spinning solution. The solution is extruded through a spinneret, a device similar to a showerhead, into a chemical bath where the strands solidify to form fibers. These fibers are then washed, stretched, and crimped to give them strength and elasticity. Finally, the fibers are spun into yarn. Acrylic yarn is known for its durability, ability to hold colors well, and resistance to wear and tear, making it a popular choice for many knitters and crocheters. However, it's less breathable than natural fibers, which can be a drawback for some projects.