Synthesis and Thermal Transition Properties of Styrene — Ethylene Oxide Block Copolymers

Crystallization Kinetics of Poly(ethylene oxide) in Poly(ethylene oxide)−Polystyrene−Poly(ethylene oxide) Triblock Copolymers

“…A melting point depression is evidenced which is more pronounced as the amorphous PS content increases in agreement with the results from the morphological and thermal studies of PS-PEO diblock copolymers. [35][36][37] In general, the melting point depression implies reduction of the crystalline lamellar thickness and consequently of the spherulitic size. Indeed, a comparison of the optical micrographs of the triblocks (Figure 1c,d) show a greater number of smaller spherulites for ESE-2 which is crystallized at higher supercooling (i.e., T m o -T c ) 22.5 and 18 °C for ESE-2 and ESE-1, respectively).…”

Amorphous‐Crystalline PSnPEOn Heteroarm Star Copolymers: Crystallinity and Crystallization Kinetics

“…Also, the molecular characteristics of the copolymers, such as the length of the arms and the weight content of PEO, was kept approximately the same in all the samples since it is known that these characteristics affect their crystallinity behavior. [4,5,9,10] Taking into account the above prerequisites, we attempted to investigate the possible influence of the star-shaped macromolecular architecture and, specifically, the number of arms on the crystallinity, the crystallization kinetics and spherulitic growth of the PEO blocks.…”

“…One of the systems that have received a lot of attention, is the polystyrene-block-poly(ethylene oxide) block copolymers; the study of which has been initiated since the early sixties. [1][2][3][4][5][6][7][8][9][10][11][12][13] The investigation of the crystallization behavior in amorphous-crystalline block copolymers has recently been revived emphasizing the crystallization of crystallizable blocks in nanoconfined microphases, which are defined by the amorphous blocks. [14,15] Three competing physical events (associated with the corresponding critical temperatures) have been recognized to determine the crystalline morphologies and the crystallization kinetics of the crystallizable blocks, i.e., the microphase separation (orderdisorder transition, T ODT ), the crystallization of crystallizable blocks (T c ) and the vitrification of amorphous blocks (T g a ).…”

Surface studies on multicomponent polymer systems by x-ray photoelectron spectroscopy: polystyrene/poly(ethylene oxide) homopolymer blends

“…It is instructive to compare the XPS(0) results at = 45 and 80°with the results at = 0°in Figures 1-3 for the three blends. As we discussed previously,2 the lateral and vertical homogenity of a sample can be explored by XPS (9) studies. To summarize this previous discussion, the signal intensities derived from a core level in an overlayer and in a substrate are given by eq 1 and 2, respectively.…”

“…We have ruled out the continuous overlayer model based upon the Ci8/Ol9 ratios for the PEO component. However, the slight increase in the PS to PEO relative ratios at the grazing angle (9 = 80°), where the very top surface features are enhanced, can be explained by using the surface topography models developed previously for the diblock copolymers.2® The XPS (9) studies on the three blends, when approached with the same arguments as those applied to the diblock copolymers, reach the inevitable conclusion that the PS/PEO blends have surface topographies similar to those of the PS/PEO diblock copolymers; i.e., the PS and PEO components are both exposed at the surface, and they are organized into domains that are thick compared to the XPS sampling depth. The diblock copolymers when cast as films from chloroform revealed a surface topography where the PS component was somewhat raised above the PEO component as shown in Figure 7d in the previous paper,2® and the same conclusions can be drawn for the surfaces of the blends.…”