PMID- 21848321
OWN - NLM
STAT- PubMed-not-MEDLINE
DCOM- 20120113
LR  - 20110913
IS  - 1520-5827 (Electronic)
IS  - 0743-7463 (Linking)
VI  - 27
IP  - 18
DP  - 2011 Sep 20
TI  - Shear adhesion strength of thermoplastic gecko-inspired synthetic adhesive 
      exceeds material limits.
PG  - 11278-81
LID - 10.1021/la202085j [doi]
AB  - Natural gecko array wearless dynamic friction has recently been reported for 
      30,000 cycles on a smooth substrate. Following these findings, stiff polymer 
      gecko-inspired synthetic adhesives have been proposed for high-cycle applications 
      such as robot feet. Here we examine the behavior of high-density polyethylene 
      (HDPE) and polypropylene (PP) microfiber arrays during repeated cycles of 
      engagement on a glass surface, with a normal preload of less than 40 kPa. We find 
      that fiber arrays maintained 54% of the original shear stress of 300 kPa after 
      10,000 cycles, despite showing a marked plastic deformation of fiber tips. This 
      deformation could be due to shear-induced plastic creep of the fiber tips from 
      high adhesion forces, adhesive wear, or thermal effects. We hypothesize that a 
      fundamental material limit has been reached for these fiber arrays and that 
      future gecko synthetic adhesive designs must take into account the high adhesive 
      forces generated to avoid damage. Although the synthetic material and natural 
      gecko arrays have a similar elastic modulus, the synthetic material does not show 
      the same wear-free dynamic friction as the gecko.
CI  - (c) 2011 American Chemical Society
FAU - Gillies, Andrew G
AU  - Gillies AG
AD  - Department of Mechanical Engineering, University of California, Berkeley, 
      California 94720, USA. andrew.gillies@berkeley.edu
FAU - Fearing, Ronald S
AU  - Fearing RS
LA  - eng
PT  - Journal Article
DEP - 20110823
PL  - United States
TA  - Langmuir
JT  - Langmuir : the ACS journal of surfaces and colloids
JID - 9882736
EDAT- 2011/08/19 06:00
MHDA- 2011/08/19 06:01
CRDT- 2011/08/19 06:00
PHST- 2011/08/19 06:00 [entrez]
PHST- 2011/08/19 06:00 [pubmed]
PHST- 2011/08/19 06:01 [medline]
AID - 10.1021/la202085j [doi]
PST - ppublish
SO  - Langmuir. 2011 Sep 20;27(18):11278-81. doi: 10.1021/la202085j. Epub 2011 Aug 23.