Final answer:
A salamander utilizing hydrogen bonds to cling to surfaces would find it most difficult to adhere to plastic surfaces because of its non-polar nature, which resists the formation of hydrogen bonds and leads to weaker adhesive forces.
Step-by-step explanation:
If a salamander clings to surfaces through hydrogen bonds, it would have the most difficulty clinging to a plastic surface. This is because adhesive force and surface tension play crucial roles in how well a salamander can cling. Typically, hydrogen bonds are more effectively formed with materials that are polar, like water and glass, because they have a charge distribution that can attract the salamander's limbs.
Materials like wood and metal also have some level of polarity and a capacity to form these bonds, albeit not as effectively as glass. However, many plastics are non-polar and have surfaces that resist the formation of hydrogen bonds, causing the adhesion to be much weaker. Therefore, salamanders would struggle most with clinging to plastic surfaces due to the minimal adhesive force between their limb's secretions and the plastic.
Surface tension contributes to this phenomenon substantially. It is the cohesive force that causes molecules at the surface of a liquid to stick together, like water droplets beading on a car's waxed paint rather than flattening out. The contact angle of the droplet indicates the relative strength of cohesive versus adhesive forces. On a plastic surface, the cohesive forces between water molecules are often greater than the adhesive forces between the water and the plastic, leading to poor cling ability for the salamander.