We report on the effect of interfacial energy on the glass temperature, T g , of several amorphous polymers with various glass temperatures and polymer/substrate interactions confined within self-ordered nanoporous alumina (AAO). The polymers studied include poly(phenylmethylsiloxane) (PMPS), poly(vinyl acetate) (PVAc), 1,4-polybutadiene (PB), oligostyrene (PS), and poly(dimethylsiloxane) (PDMS). The segmental dynamics and associated T g 's are studied by means of dielectric spectroscopy. The interfacial energy for the polymer/substrate interface, γ SL , is calculated with Young's equation whereas the AAO membrane surface energy is obtained by measuring contact angles for several reference liquids. We find that interfacial energy plays a significant role in the segmental dynamics of polymers under confinement within AAO. There is a trend for a decreasing glass temperature relative to the bulk with increasing interfacial energy. PDMS exhibits the highest interfacial energy and the highest reduction in glass temperature within AAO. Other effects that may also contribute to changes in T g are discussed.

The dynamics of unentangled cis-1,4-polyisoprene confined within self-ordered nanoporous alumina (AAO) is studied as a function of molecular weight (5000–300 g/mol) and pore size (400–25 nm) with dielectric spectroscopy. The main effects are the pronounced broadening of both segmental and chain modes with decreasing AAO pore diameter. This suggests that the global chain relaxation is retarded on confinement. Remarkably, the distribution of relaxation times is broadened even within pores with size 50 times the unperturbed chain dimensions. The glass temperature is unaffected by confinement. These results are discussed in terms of confinement and adsorption effects. Confinement effects are negligible for the studied molecular weights. Chain adsorption, on the other hand, involves time and length scales distinctly different from the bulk that can account for the experimental findings.

Capillary penetration of a series of entangled poly(ethylene oxide) melts within nanopores of self-ordered alumina follows an approximate t behavior according to the Lucas-Washburn equation; t is the time. However, the dependence on the capillary diameter deviates from the predicted proportionality to d; d is the pore diameter. We observed a reversal in the dynamics of capillary rise with polymer molecular weight. Chains with 50 entanglements (M ≤ 100 kg/mol) or less show a slower capillary rise than theoretically predicted as opposed to chains with more entanglements (M ≥ 500 kg/mol) that display a faster capillary rise. Although a faster capillary rise has been predicted by theory and observed experimentally, it is the first time to our knowledge that a slower capillary rise is observed for an entangled polymer melt under conditions of strong confinement (with 2R/d = 1). These results are discussed in the light of theoretical predictions for the existence of a critical length scale that depends on the molecular weight and separates the microscopic (d < d) from the macroscopic (d > d) regime.

The dynamics of a series of entangled cis-1,4-polyisoprenes located within self-ordered nanoporous alumina templates are studied as a function of the degree of confinement, 2R g /d (R g is the radius of gyration and d is the pore diameter) with dielectric spectroscopy and temperature-modulated differential scanning calorimetry. For the higher molecular weights, the segmental dynamics obtained on cooling speed-up under confinement resulting in a lower glass temperature, T g , with respect to the bulk, scaling as ΔT g = −62 × (2R g / d). This effect is discussed in terms of the proposed relation of the glass temperature to the interfacial energy. Under confinement, a new process appears with an Arrhenius temperature dependence and with a dielectric strength that increases linearly with the increasing degree of confinement. This mode is discussed in terms of the adsorption/desorption kinetics of segments in the vicinity of the pore walls. The particular geometry employed here with the electric field being parallel to the polymer/surface interface maximizes the contribution of adsorbed segments. Moreover, with temperature-modulated differential scanning calorimetry and dielectric spectroscopy, we address the origin of the dual glass temperature, T g , found on the heating traces. By employing several temperature/annealing protocols, we show that the higher T g is conditional; it appears only when the lower T g is crossed on the previous cooling run. These findings could suggest that the lower T g is the one closer to equilibrium.

Statistical and block copolymerization of poly(L-lactide) (PLLA) and poly(ε-caprolactone) (PCL) macromonomers having an end-norbornenyl group was performed via ring opening metathesis polymerization, ROMP, to produce the corresponding statistical and block brush copolymers consisting of PLLA and PCL side chains on a polynorbornene, PNBE, backbone. The molecular characteristics of the macromolecular brushes were determined by 1 H-NMR spectroscopy and Size Exclusion Chromatography equipped with various detectors. These complex topologies allow addressing important questions on the physics of semicrystalline polymers. These include the role of (i) a doubly grafted PCL or PLLA chain on