Determination of hydrogen depth profiles in polymer films by the 15N nuclear reaction technique

Dewetting of Thin Diblock Copolymer Films: Spinodal Dewetting Kinetics

“…In general, PpMS prefers to segregate at the film surface due to the large differences in the surface energies of both components PS and PpMS (γ(PpMS)/γ(PS) = 0.86). Whereas in thick films the lamellar order induced by this surface segregation decays toward the bulk, in thin films the ratio of film thickness l and lamellar spacing L becomes important. − In the model system P(S- b -pMS) the lamellar order is installed right after preparation as well as after annealing. , However, the initial periodicity L̃ = 240 ± 10 Å, which commonly installs right after preparation in the case of thick P(S- b -pMS) films, , is smaller than the bulk lamellar period L . In the case of 300 Å film thickness the surface tension force a surface segregation of PpMS, but the limited available volume of polymeric material ( l = 6 L̃ /5 = 2 L /3) prevents the buildup of a complete lamella.…”

“…The film thickness was again determined with X-ray reflectivity right after preparation. As compared to the bulk lamellar period L = 450 Å, − this corresponds to nearly three lamellae ( l = 11 L /4). During the annealing within 4157 h no sign of dewetting, like first holes, or a significant roughening of the diblock copolymer film surface was observable with SFM or X-ray scattering.…”

“…The model system chosen is poly(styrene- block - p -methylstyrene), denoted P(S- b -pMS), which is characterized by the weak incompatibility of both components polystyrene (PS) and poly( p -methylstyrene) (PpMS) − and the strong surface segregation of the PpMS component. , Consequently, a lamellar order is already installed right after preparation. Its periodicity is different as compared to the equilibrium bulk state, and it rearranges during annealing. , In the case of very thin films the PpMS component likes to wet both interfaces.…”

Phase and Microphase Separation of Polymer Thin Films Dewetted from Silicon—A Spin–Echo Resolved Grazing Incidence Neutron Scattering Study

“…The value Λ 0 = 45 nm has been obtained from the hydrogen depth profile measured in thick P(Sb-pMS) films by the 15 N nuclear-reaction technique. 39,40 With storage under toluene vapor, a destabilization of confined diblock copolymer films with thicknesses h < 2R g becomes possible (storage time of 12 h).…”

“…With decreasing film thickness, however, the confinement gives rise to an interplay between the intrinsic length scale of the bulk structure (bulk lamellar period, Λ 0 ) and the geometry of the film. The value Λ 0 = 45 nm has been obtained from the hydrogen depth profile measured in thick P(S- b -pMS) films by the 15 N nuclear-reaction technique. , With storage under toluene vapor, a destabilization of confined diblock copolymer films with thicknesses h < 2 R g becomes possible (storage time of 12 h).…”