Block copolymers were prepared by copolymerization of ethylene
oxide and butylene oxide to have identical
overall composition and chain length but to differ in their
distributions of oxyethylene (E) block length by
virtue of the sequence of polymerization of the two monomers:
ethylene oxide first to obtain copolymer
E41B8, and butylene oxide first to obtain
B8E41. Gel permeation chromatography was
used to show that the
chain length distributions were in accord with the prediction of the
kinetic scheme of Weibull and Nycander.
The effect of E-block-length distribution on the self-association
(micellization) of the two copolymers in
water was determined by means of surface tension and light scattering
(dynamic and static) measurements.
Compared with copolymer E41B8 under
similar conditions, it was found that copolymer
B8E41 micellized
more readily and formed larger micelles. The effect of the
difference in micellar properties on the gelation
of moderately concentrated solutions of the two copolymers is described
and discussed.
Data availabilitySummary statistics generated by COVID-19 Host Genetics Initiative are available online (https://www.covid19hg.org/results/r6/). The analyses described here use the freeze 6 data. The COVID-19 Host Genetics Initiative continues to regularly release new data freezes. Summary statistics for samples from individuals of non-European ancestry are not currently available owing to the small individual sample sizes of these groups, but the results for 23 loci lead variants are reported in Supplementary Table 3. Individual-level data can be requested directly from the authors of the contributing studies, listed in Supplementary Table 1.
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