Results show that as sti�ness increases, the friction is not a�ected
0
0.5
1
1.5
2
2.5
3
3.5
4
20 25 30 35 40 45 50 55
Fric
tion,
N
Shore A Value
34
25.4
47.4
42.7
49.625
0
10
20
30
40
50
60
0% 5% 10% 15% 20% 25% 30% 35%
Shor
e A
Val
ue
Weight Percent of Iron (III)Oxide
Made several samples with di�erent weight percent of Iron (III) Oxide.
Results
Dispersed particles create a sti�er PDMS without a�ecting the friction force.
We successfully fabricated PDMS pillars with embedded particles.
Conclusions
Friction TestSti�ness Test
Test surface
Pulley
Weight = Friction
RubberMetal load (20 g)
Fibrillar array
Test Methods
1g PDMS
0.1 g curing agent
Stir Molding on
Si Template
Vacuum
eliminatebubbles
Oven cure
~60 ℃ 2 hoursPDMS
X grams of Iron (III)
Oxide
Stir10 µm
Many people have tried to mimick the feet of geckos with soft PDMS, a type of synthetic rubber.
Procedure
Si
PDMS
Si
We intend to create a sti�er PDMS by embedding Iron (III) Oxide particles in the sample
Soft PDMS sticks well, but there are some mechanical stability issues:
Clumping, material strength.
Clumping
Objective
Geckos feet contain setae, which are responsible for the climbing properties of these animals. The �brillar array conforms to the surface, which increases the Van der Waals force interaction.
Normal Interface Fibrillar Interface
Fabrication and Friction Properties of PDMS Pillars with Embedded Particles
Manuel Leyva, Yongkwan Kim, Ye Tian, Roya MaboudianApplied Materials and Surface Science Laboratory, University of California, Berkeley
Introduction
Changing the amount of curing agent used for the preparation of PDMS altered the sti�ness of the sample.
Ratio Between PDMS and Curing Agent Durometer Reading10 to 0.5 20.310 to 1.0 43.210 to 1.5 49.2
0
0.5
1
1.5
2
2.5
3
0 10 20 30 40 50 60Fri
ctio
n, N
Durometer Reading
As pure PDMS becomes sti�er, the friction force decreases.
Soft PDMS, a synthetic rubber known for its adhesive properties, has previously been used in an e�ort to mimick the feet of geckos. However, soft PDMS has mechanical stabiltyissues, like clumping and material strength. By dispersing Iron (III) Oxide into the PDMS sample, the sti�ness is increased while the friction force remains una�ected.
Acknoledegments: National Science Foundation, Transfer-to-Excellence Research Experience for Undergraduates, Applied Materials and Surface Science Laboratory, Yongkwan Kim, Ye Tian,Roya Maboudian
Future Work
Con�rm the dispersion of particles atmicro scale.
Perform reproducibility tests to decreaseerror bars.
Test longer and thinner length �bers. Testand compare with previous work.
