Untitled

Singh, Mohit; Trivedi, M.K.; Bellare, Jayesh

doi:10.1023/a:1004796921503

Cited by 17 publications

(8 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The low count for the C 12 Ala surfactant at lower concentrations indicates that the aggregates present in solution are small spherical micelles that have diameters typically in the range of 3-5 nm. 68 The intensity distribution graphs of both amphiphiles are depicted in Figure 8. The size distribution in a 20 mM solution of C 12 Ala is shown in Figure 8a.…”

Section: Resultsmentioning

confidence: 99%

Effect of Hydrogen Bonding on the Physicochemical Properties and Bilayer Self-Assembly Formation ofN-(2-Hydroxydodecyl)-l-alanine in Aqueous Solution

Ghosh

Dey

2008

Langmuir

View full text Add to dashboard Cite

The aggregation behavior of N-(2-hydroxydodecyl)-L-alanine (C12HAla) and N-(n-dodecyl)-L-alanine (C12Ala) was studied in aqueous buffer (pH 12) over a concentration range above their critical aggregation concentration (cac). The C12HAla amphiphile has two cacs in contrast to only one cac value for C12Ala. The micropolarity and microviscosity of the aggregates were studied by use of pyrene and 1,6-diphenyl-1,3,5-hexatriene, respectively, as fluorescent probes. Dynamic light scattering was used to measure the average hydrodynamic diameter and size distribution of the aggregates. Large size, high microviscosity, and low micropolarity values of the aggregates suggested the formation of bilayer structures in dilute solutions of C12HAla. In contrast, C12Ala was observed to form micelles. Transmission electron micrographs of dilute and moderately concentrated solutions of C12HAla revealed the existence of spherical vesicles and branching tubular structures, respectively. Comparison of the aggregation behavior of these amphiphiles to that of C12Ala and the FT-IR spectrum suggested that intermolecular hydrogen-bonding interactions between adjacent hydrocarbon chains through the -OH and -NH- groups of C12HAla are responsible for bilayer formation. The mechanism of nanotube formation was discussed. The temperature dependence of aggregate formation of the amphiphile also was investigated.

show abstract

Section: Resultsmentioning

confidence: 99%

Effect of Hydrogen Bonding on the Physicochemical Properties and Bilayer Self-Assembly Formation ofN-(2-Hydroxydodecyl)-l-alanine in Aqueous Solution

Ghosh

Dey

2008

Langmuir

View full text Add to dashboard Cite

show abstract

“…The aggregates are found to be much larger in size than small spherical micelles which have diameters typically in the range 3-5 nm. 63 The d H values of the aggregates in 0.5 mM (pH 8) are found to be in the range of 30-200 nm, whereas those in 2.0 mM (pH 12) solution of SOBH the particle size is in the range 60-300 nm. In both pHs, the volume fraction of the larger size particles is much lower compared to the small size particles.…”

Section: Hydrodynamic Size Of the Aggregatesmentioning

confidence: 94%

Spontaneous formation of pH-sensitive, stable vesicles in aqueous solution of N-[4-n-octyloxybenzoyl]-l-histidine

2010

View full text Add to dashboard Cite

We report the construction of novel temperature-responsive assemblies based on a double hydrophilic block copolymer (consisting of a PEG block and a β-cyclodextrin-containing block, PEG-b-PCD) and poly(N-isopropylacrylamide) (PNIPAm). Thus formed nano-assemblies exhibit a spherical morphology and have a temperature-responsive loose core. The driving force for the formation of these assemblies was found to be the inclusion complexation interaction between the hydrophobic cavity of β-cyclodextrin and the isopropyl group of PNIPAm. The particle size of these assemblies changed reversibly in response to the external temperature change. The particle size also changed with the PNIPAm/PEG-b-PCD weight ratio. A model hydrophobic drug (indomethacin) was loaded into these assemblies with a high efficiency. An in vitro release study showed that the payload could be released in a sustained manner after an initial burst release. The release rate could be switched between high and low in an ON/OFF fashion by temperature. These results demonstrate that the nano-assemblies have high potential for applications in controlled drug delivery and biomedicine when temperature responsiveness is desired.

show abstract

“…[23][24][25][26] The mechanism of operation of OECTs based on PEDOT:PSS has been described elsewhere. 14 To detect changes due to the formation of micelles, the OECT modulation |(I À I 0 )/I 0 |, where I is the off source-drain current (for gate voltages, V g s 0 V) and I 0 is the on source-drain current (for V g ¼ 0 V), was measured as a function of the CTAB concentration, varying V g between 0 and 1 V and keeping the drain-source voltage (V d ) constant at À0.4 V. A different behaviour is found for OECTs employing NaCl as electrolyte, whose off current does not depend on the electrolyte concentration.…”

Section: Device Fabricationmentioning

confidence: 99%

“…As the electrolyte, we employed CTAB aqueous solutions at concentrations ranging from 1 Â 10 À6 M to 1 Â 10 À2 M. The diameter of the CTAB micelles, estimated by dynamic light scattering measurements at a CTAB concentration of 1 Â 10 À2 M, was determined to be about 4 nm, in agreement with values reported in the literature. [23][24][25][26] The mechanism of operation of OECTs based on PEDOT:PSS has been described elsewhere. 14 To detect changes due to the formation of micelles, the OECT modulation |(I À I 0 )/I 0 |, where I is the off source-drain current (for gate voltages, V g s 0 V) and I 0 is the on source-drain current (for V g ¼ 0 V), was measured as a function of the CTAB concentration, varying V g between 0 and 1 V and keeping the drain-source voltage (V d ) constant at À0.4 V.…”

Section: Device Fabricationmentioning

confidence: 99%

Organic electrochemical transistors monitoring micelle formation

et al. 2012

View full text Add to dashboard Cite

Organic electrochemical transistors (OECTs) exploit electrolyte gating to achieve the transduction of ionic currents. Therefore, they are ideally suitable to sense different chemo/bio species dissolved in the electrolyte. Current modulation in OECTs relies on doping or dedoping of the OECT channel by electrolyte ions. Nevertheless the role played by the specific physicochemical properties of an electrolyte on OECT operation is largely unknown. Here we investigate OECTs, making use of aqueous solutions of the micelle-forming cationic surfactant cetyltrimethylammonium bromide (CTAB) as the electrolyte. Micelle-forming salts are remarkable model systems to study the doping and dedoping mechanism of OECTs, because the aggregation of dissociated ions into micelles at the critical micelle concentration permits to modify the size and the type of the species that dope or dedope the OECT channel in situ. The current modulation of OECTs using a CTAB electrolyte shows a marked increase close to the critical micellar concentration. The measurement of the transistor's drain current as a function of CTAB concentration provides a simple, fast method to detect the formation of micelles from dissociated ions.

show abstract

Untitled

Cited by 17 publications

References 6 publications

Effect of Hydrogen Bonding on the Physicochemical Properties and Bilayer Self-Assembly Formation ofN-(2-Hydroxydodecyl)-l-alanine in Aqueous Solution

Effect of Hydrogen Bonding on the Physicochemical Properties and Bilayer Self-Assembly Formation ofN-(2-Hydroxydodecyl)-l-alanine in Aqueous Solution

Spontaneous formation of pH-sensitive, stable vesicles in aqueous solution of N-[4-n-octyloxybenzoyl]-l-histidine

Organic electrochemical transistors monitoring micelle formation

Contact Info

Product

Resources

About