A completely controlled sphere-to-bilayer micellar transition: the molecular mechanism and application on the growth of nanosheets

Abstract

The combination of a simple modification of the sample addition method to generate a sort of continuously accumulated external stimulation with only minute increments in amplitude and the introduction of probe molecules (herein aniline) within the micelle allow the direct continuous in situ spectroscopic monitoring of possible micellar transitions. In this way, a sphere-to-ellipsoid and further an ellipsoid-to-bilayer micellar transition of sodium dodecyl sulfate (SDS) induced by camphor sulfuric acid (CSA) is observed to experience four stages in the time sequence: (i) the accumulated protons released from CSA in the hydration layer of the micelle stimulate the rearrangement of SDS micelles; (ii) the micelles transform into ellipsoidal shapes as evidenced by the characteristic chemical shift anisotropy and the corresponding molecular dynamic properties from probe molecules; (iii) further protonation of aniline induces the micelle to turn into lamellar structures; (iv) aniline is freed from the micelle while leaving the SDS bilayers undistorted. Moreover, polyaniline nanosheets incorporating SDS bilayers in sandwich structures, which can display excellent capacitive behavior at relatively high current densities for the fabricated supercapacitors, are prepared from the aniline oriented by the bending energy of the SDS bilayers.

Shape-controlled synthesis of one-dimensional cesium lead halide perovskite nanocrystals: methods and advances

“…43 The micellar transition mechanism, namely sphere-like micelles grow into different shapes at different ligand pair and solvent conditions, is considered to explain these results. 74,75…”

Comparative Study of the Formation Mechanism of Polyaniline Nanorods and Nanotubes Through In Situ NMR Technique

“…Although these theories explain the formation mechanism of polyaniline nanotubes, they fail to explain the driving force of these spherical micelles to turn into rods or curl themselves on a molecular level. To solve the problem, in situ NMR technique is applied to study the nucleation mechanism of PANI, our team [15][16][17][18][19][20] have studied the nucleation mechanism of PANI nanosheets, nanofibers, nanotubes and hollow microspheres through in situ 1 H NMR and kinetic experiments including 1D NOE and T 1H , in combination with TEM, which indicates that the movement of water molecule including hydrated water can reflect the nucleation sensitively, in particular in the process of the structural transition. Meanwhile, it is found that PANI nanorods were synthesized at the low concentration of SA while PANI nanotubes were obtained at the high concentration of SA.…”

Nucleation of Polyaniline Microspheres and Interconnected Nanostructures from Strongly Coupled Micelle-like Systems

“…Being one of the ubiquitous operations in industry and daily life, the phenomenon of nucleation has attracted a worldwide research interest. − Particularly, the rapid development of nanoscience and nanotechnology has prompted this progress even further. , Being stabilized by the surfactant molecules, the originally less controllable nuclei incline to adopt some specific nucleation pathways and results in the products to exhibit specific morphologies. Over the past few decades, many spectroscopic measurements have been carried out on a large family of micellar systems in an effort to uncover the step-wised procedures and key factors accounting for the activity and selectivity of the nuclei for nanoparticles. , …”

“…Over the past few decades, many spectroscopic measurements have been carried out on a large family of micellar systems in an effort to uncover the step-wised procedures and key factors accounting for the activity and selectivity of the nuclei for nanoparticles. 7,8 Recently, the nucleation in micelle-like systems has become another hot topic. 9−11 Compared with the conventional micelles, the micelle-like ones are compacted together through weak, short-ranged, and reversible interactions such as ionic and hydrogen bonds, π−π stacking interactions, etc.…”