DOI: 10.1039/C5RA06339F
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In general, all gels showed a continuous gel structure under the swollen gel under cryo conditions; d) rheology of the gel swollen in
SEM. It was clearly evident from the SEM studies that a large DCM solvent.
number of porous structures could be seen in the case of organogels
In conclusion, thiol-yne reaction of PTETACT and
(
Figure 4c). This was quite obvious since the microporous gels were PETM is proved to be an efficient way for creating chemical gels. It
obtained using polymers cross-linked at the chain ends. The is important to note that the reaction is not inhibited by metal
maximum as well as uniform porous were observed in the case of catalyst or other curators since the method is not depending on the
gels swollen in DCM and CHCl solvents (Figure S9b and S9c). use of any heavy metal catalyst. FT-IR spectroscopy analysis of the
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The porous structure also observed in the case of gels swollen in cross-linked thiol-yne gel network demonstrates that the reaction
CHCl3 and DMF (Figure S9c and S9d). Interestingly the between thiol and yne in this particular system is extremely efficient.
morphology totally changed in the case of gels swollen in DMSO The triple bond conversion of the thiol-yne networks are all identical
solvent. Instead of porous structure, a fibre like morphology (Figure to the maximum possible conversion calculated from the thiol to yne
S9e) was observed in the case of gels swollen in DMSO. feed-ratio. It is interesting to note that a 1:3 molar ratios of
Surprisingly, there was a uniform pattern observed in the case of PTETACT and PETM produce the strongest gel which is
hydrogels (Figure S9f). Since the swelling was not that effective in confirmed by rheology data. The highest swelling is observed in
the case of H O, the pores observed were not too large. More DCM. The SEM image of the swollen gel in DCM shows uniform
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importantly, it was very interesting to note that the gels kept in pores present in the gel. We believe that increase in PEG content
toluene and hexane never swollen so their morphology of the surface would increase the hydrogel capabilities. The non-swelling property
as well as interior never changed at all.
of the gel in hexane and toluene has prompted us to envisage the
gel's application in removing chlorinated solvents from hydrocarbon
solvents.
GMN thanks UGC for the research fellowship and RS thanks DST,
New Delhi for Ramanujan Fellowship and IISER-Kolkata for the
infrastructure. Mr. Kashinath from Carl Zeiss India, is acknowledged
for the help in capturing quality SEM pictures.
Notes and references
Polymer Research Centre, Department of Chemical Sciences,
Electronic Supplementary Information (ESI) available: Supporting
information includes synthetic procedure, TGA and additional
analytical data. This material is available free of charge via the
Internet at DOI: 10.1039/c000000x/
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Figure 4. a) Cartoon representation of the 3 D networking; b)
swelling efficiency of gel in different solvents; c) SEM image of
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