I used light scattering to examine alkynyl-end capped PEO chains with Molecular weight of 10000g/mol in aqueous solution(0.8mg/ml). However,as common sense suggests, polymer chains should be dispersed well in single chain form in good solvents(I examined that pure PEO with -OH end capped show well single chain signal at DLS and SLS without aggregates). I want to know if there are any non-covalent bonding effect among alkynyl modified PEO chains in aqueous solution? Does anyone has experienced in this issue? Thanks.
I prepared the alkynyl modified PEO in 2 steps: Firstly, 10 fold amount of NaH was added to a THF solution of HO-PEO-OH(bought from Polymer Source). Then, propargyl bromide was added dropwise to the system in ice bath. After 24h stirring at rt, the product was obtained after extraction and precipitation.
Aggregation of PEO in water of very low concentration (between 10^-6 and 10^-5 of the chain concentration) was recorded in several SANS experiments (see publication in present issue of Macromolecules) which even enhanced at temperatures above 70°C. We also observed such behavior in PEGMA with SANS but did not publish yet. So I could imagine that alkynyl modified PEO chains would show similar aggregation behavior which of course has to be verified by experiment.
My best regards
Dietmar Schwahn
Yes it does: there is some literature on the assembly of "completely hydrophilic" polymers in water, see e.g. the work of Helmut Schlaad. We also had one study on the self-assembly on PEO-based block copolymers - where PEG turned out to be the less water-soluble block: http://pubs.acs.org/doi/abs/10.1021/ma300621g
Best of luck with your research, Andreas
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