TY  - THES
T1  - Switchability induced by mechanical instability in bioinspired adhesives
A1  - Paretkar,Dadhichi R.
Y1  - 2012/07/23
N2  - Non-covalent adhesion produced by the gecko is attributed to the structured surface of its toes. The synthetic adhesives mimicking this principle have now been around for a decade. However, the characteristic features of reversibility and self-cleaning ability of the gecko adhesive system have not yet been successfully integrated. The present work focuses on developing a switchable adhesive system responsive to an external stimulus. Elastomeric polydimethylsiloxane surfaces are structured with fibrillar arrays. Mechanical instability of the fibrils is recognized and utilized to produce a reversible switch between adhesion and non-adhesion. Normal compression caused the fibrils to buckle inducing a contact transition from their tips to the sides. When the contact transition occurred under moderate compressive loads, tip contact re-formed upon reversal of buckling and adhesion was reversible. However, when reversible buckling occurred under large compressive loads or when fibril side peeled without unbuckling, contact re-formation was impaired. Drastic change incontact area in the re-formed state resulted in a low adhesion state. The role of fibril contact shape, radius, aspect ratio, orientation and the applied compressive load in the adhesion switchability was examined. In situ visualization was employed to study the contact mechanisms. Contact shape, fibril orientation and preload were identified as the key parameters for controlling switchable adhesion.
KW  - Biomimetikum
KW  - Adhäsion
KW  - Polydimethylsiloxane
CY  - Saarbrücken
PB  - Universitäts- und Landesbibliothek
AD  - Postfach 151141, 66041 Saarbrücken
UR  - http://scidok.sulb.uni-saarland.de/volltexte/2012/4905
ER  -