Temperature-responsive self-assembled nanostructures from lysine-based surfactants with high chain length asymmetry: from tubules and helical ribbons to micelles and vesicles

• Type: Article in International Scientific Journal
• Date: 2019

Authors

Oliveira, IS (Author) Other; Lo, M (Author) Other; Maria J Araujo (Author) FCUP; Eduardo F Marques (Author) FCUP

Journal

Title: Soft Matter

Vol. 15

Pages: 3700-3711

ISSN: 1744-683X

Publisher: Royal Society of Chemistry

Indexing

ISI Web of Knowledge - 17 Citations

Scopus - 18 Citations

Other information

Authenticus ID: P-00Q-EV8

DOI: 10.1039/c9sm00399a

Abstract (EN): Stimuli-sensitive self-assembled nanostructures are of great relevance for the templating of nanomaterials and the design of efficient systems for the controlled delivery of molecules. Amino acid-based surfactants often display such fascinating self-assembly due to a combination of molecular features such as critical packing parameter, chirality and H-bonding interactions. Herein, we focus on a family of newly synthesized double-chained alkylcarboxylates derived from L-lysine, and designated by 8Lysn, mLys8, with n, m = 12, 14 and 16, and 12Lys16 and 16Lys12, where the numbers represent the number of C atoms in each hydrocarbon chain. The effects of the chain length asymmetry and structural isomerism of the surfactants on their interfacial properties, thermal behavior and self-assembly in water were investigated by a comprehensive toolbox, including surface tension, DSC, imaging (light microscopy, SEM, TEM and AFM) and SAXS. All the surfactants below their Krafft temperature self-organize into tubular structures of various morphologies (flat structures, twisted and coiled ribbons and hollow tubes), forming hydrogels at low surfactant concentration. Upon the solubilization phase transition, micelles or vesicles are formed depending on the surfactant structure, and the tubule-micelle or tubule-vesicle transition is thermoreversible. A molecular-level rationalization of the observed self-assembly and phase transition features is put forth.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 12