The Water Race: Hydrophobic & Hydrophilic Surfaces (High School curriculum lesson)

water droplet
NNIN logo
Linked product
Description: 

This activity developed by NNIN explores how nanotechnology can be used to change the properties of a copper surface so that it either attracts or repels water. It is appropriate for middle school and high school students.

Nonpolar molecules that repel the water molecules are said to be hydrophobic; molecules forming ionic or a hydrogen bond with the water molecule are said to be hydrophilic. This property of water was important for the evolution of life. Hydrophobic interaction plays the most critical roles in the formation of the lipid bilayer of the cell membrane and the folding of proteins and nucleic acids; therefore, hydrophobic interaction is the foundation for the existence of life. A self-assembled monolayer (SAM) is a layer of organic molecules formed spontaneously on a solid substrate. One end of the organic molecule binds to the solid surface via a covalent bond while the other end points outwards. Because the exposed end of the SAM determines the surface properties of the SAM modified substrate, we can alter a hydrophobic surface (a surface that expels water) into a hydrophilic surface (a surface that attracts water) by carefully selecting the SAM forming molecules.

This lesson requires the use of special chemicals which can be ordered from standard supply houses.

Audience: 

Objectives

NISE Net Content Map: 
  • Nanometer-sized things are very small, and often behave differently than larger things do.
  • Scientists and engineers have formed the interdisciplinary field of nanotechnology by investigating properties and manipulating matter at the nanoscale.
  • Nanoscience, nanotechnology, and nanoengineering lead to new knowledge and innovations that weren't possible before.

Credits

Funding: 
National Nanotechnology Infrastructure Network (NNIN) funded by the National Science Foundation
Owning institution: 
National Nanotechnology Infrastructure Network (NNIN); © 2006 Alonda Droege and the University of Washington
Permissions: 

This linked product was created by another institution (not by the NISE Network). Contact owning institution regarding rights and permissions.