Módulo Instruccional

Catalytic motors

Audience

High school students (8 – 12)

Time frame

Set-up: 5 minutes

Activity: 40 minutes

Clean up: 5 minutes

Standard and educational expectations 

Estándar: Estructura y niveles de organización de la materia                      

Diseño  de Ingeniería

Expectativas: Q.CF1 – La materia y sus interacciones: Interacción y energía

                                 Q.I.T1  -  Diseño para ingeniería

Indicadores: ES.Q.CF1.IEM. 19

                             ESQCF1.CC 7

                                           ESQIT1.IT1, 2.4 Y 5

Objective(s)

After completing the activity, students will be able to:

1. Explore the motion of a Janus particle through the construction of a macro scale “nanomotor”

2. Observe the behavior of a “nanomotor” focusing on the differences and similarities between Brownian motion and the autonomous motion.

3. Distinguish between different types of propulsion

Materials (For each group)

Vinegar 5%

Foam plate

Sodium bicarbonate

Two rectangular containers

Ruler

Permanent markers

Scissors

Safety equipment- Glove and glasses

Activity Instructions

Set-up (5 min) 

Safety Instructions: Safety gloves and glasses should be worn at all times. 

Sodium bicarbonate MSDS - http://www.sciencelab.com/msds.php?msdsId=9927258

Potential Acute Health Effects: Slightly hazardous in case of skin contact(irritant), of eye contact(irritant), of ingestion, of inhalation

Acetic Acid 5%(Vinegar) MSDS - http://www.sciencelab.com/msds.php?msdsId=9925518

Potential Acute Health Effects:

Hazardous in case of skin contact (irritant), of eye contact (irritant), of ingestion, of inhalation. Slightly hazardous in case of skin contact (permeator), of ingestion

Introduction (10 min) 

Before the activity, students should have studied in class the following concepts:

1. Solutions

2. Heterogeneous mixtures

2. Suspensions and Colloids

3. Brownian Motion 

Begin the activity with the video of the Brownian motion of a nanoparticle.

Recommendations: http://www.youtube.com/watch?v=hy-clLi8gHg&feature=related

        http://www.youtube.com/watch?v=cDcprgWiQEY&feature=c-shelf-119

Then, explain that there is a nanoparticle known as Janus, characterized by having dual functionality. In addition, indicate that this particle has a Brownian motion but also, under specific conditions, may show autonomous movement. Janus particles move autonomously due to different mechanisms: a) concentration gradients (diffusiophoresis) b) temperature gradients (thermophoresis) c) magnetic gradients (magnetophoresis), d) surface tension gradients (Marangoni propulsion) and e) Bubble propulsion

The mechanism of this activity will be bubble or Jet propulsion. In this part explain the concepts:

In this type of propulsion mechanism, bubbles of products are generated from the reaction. These bubbles impart propulsion on the object due to pressure increase or momentum recoil when they burst. In our activity, the bubbles will be formed due to carbon dioxide (CO2) product of the reaction between Sodium Bicarbonate and Vinegar

Construction of Catalytic “nanomotor” with bubble propulsion mechanism:

Teacher: This activity can be done in groups of two students. Once each group has the set of materials, the following procedure must be followed:

Using the ruler draw a 5 cm x 2 cm rectangle over the foam plate

Cut carefully the rectangle with the knife

Draw a line in the center of the rectangle to divide in two sides

Brush on half of the rectangle with glue. Enough to wet the surface with a thin layer on both sides. 

Plunge the glued half of the rectangle into the Sodium Bicarbonate. Wait some minutes and remove. Remove excess. Wait 5 - 10 minutes until glue dries out. 

 Use the markers to color the other side of the rectangle to distinguish the unreactive half of the “Janus” particle.

In the container pour the vinegar about 2 inches from the bottom.

References:

S. Bamrungsap, J. A. Phillips, X. Xiong, Y. Kim, H. Wang, H. Liu, A. Hebard, and W. Tan, (2011). Magnetically driven single DNA nanomotor, Small, vol. 7, no. 5, p. 60.

T. E. Mallouk and A. Sen, "Powering nanorobots," Scientific American, May 2009, pp. 72-77

J. Wang, (2013). Nanomachines: Fundamental and Application. Wiley.

Mei, Y.; Solovev, A. A.; Sanchez, S.; Schmidt, O. G., (2011). Rolled-up nanotech on polymers: from basic perception to self-propelled catalytic microengines.  Chem Soc, 40, 2109-19.

Michael Ibele, Thomas E. Mallouk and Ayusman Sen, Angew, (2009). Schooling Behavior of Light-Powered Autonomous Micromotors in Water. Chem. Int. , 48, 3308-3312.

Student task sheet: Catalytic motors

Name: ___________________________ Day: __________

Grade: ___________________ Group:_________

Intructions:

Nanomotors (10 min)  

Each group has to place the nanomotor on the surface of the water and observe. Then, each group will write a paragraph describing what was observed.

   

Reflection of learning (This part could be assigned as homework.)

How would you describe the movement of the nanomotor?

____________________________________________________________________

Indicate similarities and differences between Brownian Motion and Autonomous Motion.

Why the nanomotor stops for a moment and then moves again?

_______________________________________________________

Challenges...

What would happen if you change the shape of the nanomotor?

_________________________________________________________

What if you change its size? 

___________________________________________________________

 Can you build a carrier with a nanomotor?

_____________________________________________________________

Could you build a nanomotor that moves forward in a straight line?

______________________________________________________________