Relation between the adhesion strength and interfacial width for symmetric polystyrene bilayers

Abstract

Polystyrene (PS) bilayers were prepared and were adhered at a temperature between the surface and bulk glass-transition temperatures for a given time. Then, the interfacial adhesion strength (G L ) was examined with a conventional lapshear measurement. G L first increased with increasing adhesion time and then reached a constant value. This result implied that the segments moved across the interface, to a certain depth, even at a temperature below the bulk glass-transition temperature. To confirm this, the interfacial evolution for the PS/deuterated PS bilayers was examined with dynamic secondary-ion mass spectrometry. The G L value was linearly proportional to the thickness of the interfacial adhesion layer. Finally, we propose a strategy for regulating the adhesion strength based on the chain-end chemistry.

Autoadhesion of Glassy Polymers

“…tens-hundreds nm). [9][10][11][12][13][14][16][17][18] However, there are also some studies reported that this effect has not been observed. [19,20] So, the issue of the difference between the surface glass transition temperature (T surface g…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] This interest is caused by a significant difference in the molecular mobility revealed in those layers with respect to the interior bulk regions of the polymer sample. More specifically, an enhanced molecular motion in the nearsurface layer in comparison with that in the polymer bulk, at a constant sample temperature that is lower than the glass transition temperature of the sample bulk (T bulk g…”

“…[1][2][3][4][5][6][7][8][16][17][18] However, a better understanding of the mechanisms governing this process is still needed, in particular, concerning a key molecular property and an elementary kinetic unit of motion governing it. In this respect, the influence of bonding (or healing) time (t) and temperature (T), and of the molecular weight (M) on the interface strength may provide with useful information.…”

On the formation of topological entanglements during the contact of glassy polymers

“…The occurrence of the diffusion of chain segments at T< T bulk g across symmetric PS-PS interfaces (two pieces of one and the same polymer are in contact) has also been observed using neutron reflectivity and dynamic secondary ion mass spectroscopy techniques [9,18,19]. Moreover, it has been shown [9,18] that the kinetics law for the diffusion depth (X) at T< T bulk g is X∼t 1/4 , as in the case of σ (σ∼t 1/4 ).…”

“…In the recent years [1][2][3][4][5][6][7][8][9][10][11][12], the temperature intervals wherein the autoadhesion (bonding of one and the same material) and adhesion (bonding of different materials) between the two contacting samples of glassy polymers occur owing to the interdiffusion of chain segments across the contact zone have been revealed. The validity of this mechanism of interface healing is based on the following observations at healing temperatures (T) below the glass transition temperature of the bulk ( T bulk g ).…”