Grazing-incidence small-angle X-ray scattering studies on templating nanopores in networked polymer thin films with a multi-armed porogen

Abstract

The mechanism of thermal pore generation in organosilicate thin films loaded with a six-armed star-shaped poly( -caprolactone) porogen was quantitatively investigated by using in-situ grazing-incidence small-angle X-ray scattering and thermogravimetry. These analyses found that the blend components have a limited miscibility that depends on the composition; for porogen loadings up to only 20 wt%, molecularly miscible blend films were obtained. Even for the miscible blend films, heating the films produced a curing reaction of the precursor matrix component, leading to the phase separation of the porogen component. This phase separation was found to begin at 393 K for 10 wt% porogen loaded films and at 373 K for 20 wt% porogen loaded films, and to continue for temperatures up to 423 K. The porogen aggregates remained and were confined within the matrix film without any further growth or movement until complete thermal decomposition above 564 K.

Effect of fiber diameter on tensile properties of electrospun poly(ɛ-caprolactone)

“…The fibers experience a transition from microscale to nanoscale deformation as the size of the fiber is reduced from 1000 to 600 nm. Despite this range of fiber diameters is considerably higher than the expected radius of gyration, R g , of PCL (w2.25 nm) [26], evidence exists [7,27] that the transitional behavior in terms of the crystalline morphology takes place well above the R g values and polymer relaxation behavior drastically changes as a function of polymer film thickness [22,23,27]. The examination of the transitional mechanisms is beyond the scope of our present study.…”