Confined strings

When we combine the results of step-up and step-down in shear, we find that there is a definite vindow in shear rate across wiiich confined strings are stable. For the 10% PDMS/PIB emulsion, strings formed at 3 s are stable up to... 

Coarse graining may be combined with a confinement of the conformational space by placing the coarse grain particles on a cubic lattice. For example, Kurcinski and Kolinski (76) (CABS-REMC) represented the polypeptide chains by strings of Ca beads on a cubic lattice. Side chains were represented by up to two interaction centers, which correspond to Cp and the centers of mass of the remaining portions of the side groups, respectively. The conformational space of this model is sampled by means of a multicopy Monte Carlo method. 

Interfacial polycondensation is an interesting procedure that is often used in demonstrations in polymer chemistry courses. Polyamides are prepared rapidly, in fiont of the class, from diacid chlorides and diamines. The products are removed quickly as they form, by pulling them out as a string from the interface." Polyesters can also be prepared from diacid chlorides and bisphenols. On the other hand, preparation of polyesters from glycols and diacid chlorides is usually unsuccessful due to low reactivity of the dialcohols. The diacid chlorides tend to undergo hydrolysis instead. Commercially, this procedure is so far confined mainly to preparations of polycarbonates (discussed further in this chapter). 

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