Sodium bromide induced micelle to vesicle transitions of newly synthesized anionic surface active ionic liquids based on dodecylbenzenesulfonate.
Dodecylbenezenesulfonate-based anionic surface active ionic liquids (DBS-ILs) paired with onium cations, n-butyltrimethylammonium ([N1114]), 1-butyl-3-methylimidazolium ([C4mim]), and N-butylpyridinium ([C4Py]) have been synthesized. DBS-ILs were found to be highly surface active having critical micelle concentration (CMC) lower than that of their conventional analogue sodium dodecylbenezenesulfonate ([Na][DBS]). The CMC values of DBS-ILs were determined from surface tension (ST) and isothermal titration calorimetry (ITC). DBS-ILs formed micelles predominantly in the aqueous medium, and unlike [Na]DBS, the micelles of DBS-ILs could be transformed into vesicles with the addition of sodium bromide (NaBr). Micelle to vesicle transitions (MVTs) were evidenced from dynamic light scattering (DLS), turbidity, proton nuclear magnetic resonance ((1)H NMR), and cryo-TEM techniques. Thermodynamics of aggregation was investigated from ITC which indicated that the aggregation process is primarily driven by the entropy factor. The formation of a vesicle upon addition of NaBr has been accounted to the increased electrostatic interactions between the less hydrated sulfonate headgroup and the more populated bigger sized counterions along with the favored cation-π or π-π interactions between them as evidenced from 2D-NOESY NMR experiments. The stimuli-responsive morphological transitions in the self-assembly of the reported anionic surface active ionic liquids (SAILs) will be useful for encapsulation and delivery of active (bio)molecules in the targeted biomedical applications.
†Academy of Scientific and Innovative Research (AcSIR)-Central Salt and Marine Chemicals Research Institute, Council of Scientific and Industrial Research (CSIR), G. B. Marg, Bhavnagar 364002, Gujarat, India.
K Srinivasa
KS
Rao
†Academy of Scientific and Innovative Research (AcSIR)-Central Salt and Marine Chemicals Research Institute, Council of Scientific and Industrial Research (CSIR), G. B. Marg, Bhavnagar 364002, Gujarat, India.
Praveen Singh
PS
Gehlot
‡CSIR-Central Salt and Marine Chemicals Research Institute, Council of Scientific and Industrial Research (CSIR), G. B. Marg, Bhavnagar-364002, Gujarat India.
Hariom
H
Gupta
§Bayreuth Institute of Macromolecular Research (BIMF)-Soft Matter Electron Microscopy, Universität Bayreuth, Bld. NW II, D-95440 Bayreuth, Germany.
Markus
M
Drechsler
†Academy of Scientific and Innovative Research (AcSIR)-Central Salt and Marine Chemicals Research Institute, Council of Scientific and Industrial Research (CSIR), G. B. Marg, Bhavnagar 364002, Gujarat, India.|‡CSIR-Central Salt and Marine Chemicals Research Institute, Council of Scientific and Industrial Research (CSIR), G. B. Marg, Bhavnagar-364002, Gujarat India.
Arvind
A
Kumar
D001557:Benzenesulfonates / Q000737:chemistry*; D001965:Bromides / Q000737:chemistry*; D052578:Ionic Liquids / Q000138:chemical synthesis* / Q000737:chemistry*; D008823:Micelles; D044367:Phase Transition; D017670:Sodium Compounds / Q000737:chemistry*; D013500:Surface Tension; D013501:Surface-Active Agents / Q000138:chemical synthesis* / Q000737:chemistry*; D044366:Transition Temperature
D001557:Benzenesulfonates; D001965:Bromides; D052578:Ionic Liquids; D008823:Micelles; D017670:Sodium Compounds; D013501:Surface-Active Agents; C001114:dodecylbenzenesulfonic acid; C027938:sodium bromide