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Localized Yielding Around Crack Tips of Double‐Network Gels
Author(s) -
Tanaka Yoshimi,
Kawauchi Yasunori,
Kurokawa Takayuki,
Furukawa Hidemitsu,
Okajima Takaharu,
Gong Jian Ping
Publication year - 2008
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.200800227
Subject(s) - tearing , composite material , materials science , modulus , deformation (meteorology) , polymer , moduli , ultimate tensile strength , fracture (geology) , elastic modulus , fracture mechanics , interpenetrating polymer network , young's modulus , physics , quantum mechanics
Double‐network (DN) gels, a type of interpenetrating polymer network (IPN) consisting of rigid and flexible polymer components, exhibit two outstanding mechanical behaviors: yielding deformation of the entire specimen in tensile tests and quite high fracture energy in tearing tests. In this study, atomic force microscope (AFM) measurements were conducted on DN gels to determine the local Young's moduli immediately below the fracture surfaces E f and below the usual molded surfaces E m , and compare the local modulus with bulk Young's moduli measured before and after the yielding deformation, denoted as E h and E s , respectively. E m and E h are around 0.1 MPa; E f and E s , around 0.01 MPa, one order lower than the former two moduli. The order relation indicates that yielding deformation occurred locally around the crack tip of the DN gel during fracture. This supports the basic assumption of phenomenological models recently proposed to explain high fracture energy of DN gels. (H. R. Brown, Macromolecules 2007 , 40 , 3815–3818; Y. Tanaka, Europhys. Lett . 2007 , 78 , 56005).