Correlation between Phase Behavior and Tensile Properties of Diblock Copolymers

Abstract

The phase behavior of poly(styrene-b-butyl methacrylate), PS-b-PBMA, diblock copolymers was investigated by small-angle neutron scattering (SANS), neutron reflectometry (NR), and rheology. For a symmetrical P(dS-b-nBMA) diblock copolymer a lower critical order transition (LCOT) at 155°C was found by SANS and rheology. Furthermore, the temperature-dependent interaction parameter was determined in the temperature regime between 110 and 145°C from fits to the scattering curves in the disordered region. The interaction parameter increases with increasing temperature and shows a weak temperature dependence. The LCOT behavior thus is expected to be a large entropic contribution to . The interfacial width observed by NR is relatively large compared to other diblock copolymers. Different block copolymers were investigated with respect to the influence of miscibility on tensile properties. While poly(styrene-b-butyl methacrylate) diblock copolymers show significant synergistic effects on tensile properties, for poly(methyl methacrylate-b-butyl methacrylate) diblock copolymers no significant synergistic effects on tensile properties were observed due to the increased interaction parameter and the smaller interfacial width as compared to the case of PS-b-PBMA diblock copolymers.

Perpendicular Deformation of a Near-Single-Crystal Triblock Copolymer with a Cylindrical Morphology. 1. Synchrotron SAXS

“…Indeed, improved mechanical properties motivate the preparation of triblocks of different chemical identity. [42][43][44][45][46] However, without the ability to separate the influence of morphology from chemistry on the mechanical properties, the correlation of morphological and chemical structure with mechanical properties will remain simply a correlation.…”

Self-assembled block copolymers: Bulk to thin film

“…This transition is referred to as the lower disorder-to-order transition (LDOT). [21][22][23][24][25][26] This behavior is explained either by the equation-of-state arguments that incorporate differences in the thermal expansion coefficients or by the directional enthalpy (or entropy). 157,158 Closed-Loop Phase Behavior.…”

“…This temperature is referred to as the order-to-disorder transition temperature (T ODT ). [15][16][17][18][19][20] Some block copolymers exhibit the disorder-to-order transition (LDOT) with increasing temperature, [21][22][23][24][25][26][27][28] and a very few show the closed-loop (or immiscibility loop) phase behavior. [29][30][31][32][33][34][35][36][37] Also, the order-toorder transition (OOT) has been reported for many block copolymers when temperature is changed.…”

Non-reactive and reactive block copolymers for toughening of UV-cured epoxy coating

“…So far, thermal curing was applied in this concept which causes major problems since the crucial miscibility/non-miscibility balance of the block copolymer as well as the miscibility balance between BCP and epoxy matrix strongly depends on the temperature (note the strong temperature-dependence of the interaction parameter [29]). In this context, fast UV-induced curing reactions can be a useful technique to induce network formation at ambient temperature.…”