Clear distinction between CAC and CMC revealed by high-resolution NMR diffusometry for a series of bis-imidazolium gemini surfactants in aqueous solutions

Szutkowski, Kosma; Kołodziejska, Żaneta; Pietralik, Zuzanna; Zhukov, Igor; Skrzypczak, Andrzej; Materna, Katarzyna; Kozak, Maciej

Clear distinction between CAC and CMC revealed by high-resolution NMR diffusometry for a series of bis-imidazolium gemini surfactants in aqueous solutions

dc.contributor.author	Szutkowski, Kosma
dc.contributor.author	Kołodziejska, Żaneta
dc.contributor.author	Pietralik, Zuzanna
dc.contributor.author	Zhukov, Igor
dc.contributor.author	Skrzypczak, Andrzej
dc.contributor.author	Materna, Katarzyna
dc.contributor.author	Kozak, Maciej
dc.date.accessioned	2019-02-28T13:43:09Z
dc.date.available	2019-02-28T13:43:09Z
dc.date.issued	2018-11
dc.description.abstract	The aggregation behavior in the transition region was studied for a series of dicationic surfactants 3,3′-[α,ω-(dioxaalkane)]bis(1-dodecylimidazolium)dichlorides with varied spacer length from two to twelve carbon atoms. We employed Nuclear Magnetic Resonance diffusometry and Bayesian DOSY analysis to obtain the aggregate size distribution in the transition region. The critical concentrations CC were independently obtained from surface tension, electric conductivity, UV-Vis and NMR methods. The micelle aggregation numbers were estimated from the self-diffusion coefficients and were independently confirmed using steady-state fluorescence quenching. The morphology of the aggregates was characterized by small-angle scattering of synchrotron radiation and molecular dynamics simulations. The obtained CC values are identified as critical aggregation concentrations CAC. A broad transition region was observed, and stable micelles were obtained at much higher concentrations than CAC. The accurate CMC values could not be identified for the systems in the study. We indicated that the distribution of aggregate size becomes small and the system becomes homogeneous at much larger concentrations than CAC (typically 15–20 mM). The existence of a slow exchange between two environments, an aggregate and aqueous environment, was confirmed by 1H NMR and 2D HSQC NMR spectroscopy.	pl
dc.description.sponsorship	KS EUSMI – European infrastructure for spectroscopy, scattering and imaging of soft matter, contract number GA731019, funded under H2020-EU.1.4.1.2.RIA, MK National Science Centre (Poland)	pl
dc.identifier.citation	Szutkowski, Kosma, et al. "Clear distinction between CAC and CMC revealed by high-resolution NMR diffusometry for a series of bis-imidazolium gemini surfactants in aqueous solutions." RSC Advances 8.67 (2018): 38470-38482.	pl
dc.identifier.doi	https://doi.org/10.1039/C8RA07081D
dc.identifier.uri	http://hdl.handle.net/10593/24421
dc.language.iso	eng	pl
dc.publisher	RSC	pl
dc.rights	info:eu-repo/semantics/openAccess	pl
dc.subject	Self-diffusion	pl
dc.subject	Diffusion NMR	pl
dc.subject	SAXS	pl
dc.subject	FT-IR	pl
dc.subject	UV-VIS	pl
dc.subject	Electric conductometry	pl
dc.subject	Gemini surfactants	pl
dc.subject	CMC	pl
dc.subject	CAC	pl
dc.subject	Aggregation	pl
dc.title	Clear distinction between CAC and CMC revealed by high-resolution NMR diffusometry for a series of bis-imidazolium gemini surfactants in aqueous solutions	pl
dc.type	Inne	pl