Unique nanoscale morphologies underpinning organic gel-phase materials

A R Hirst, D K Smith, J P Harrington

Research output: Contribution to journalArticlepeer-review

Abstract

This study investigates the self-assembly of simple aliphatic diamines with a dendritic peptide. By controlling the molar ratio of this twocomponent system, new nanoscale morphologies were generated. In the presence of relatively long aliphatic chains (C10, C12) a transition from nanoscale fibres to platelets was observed on changing the molar ratio, whereas, for shorter spacer chains (e.g., C9 and C8), interesting and unique morphological changes were observed by low voltage field emission gun scanning electron microscopy (SEM), with "nanosquares" or nanoscale "rosette" structures being formed. Remarkably, these discrete nanoscale structures were able to form sample-spanning networks capable of supporting a gel-phase material; whereas, most gels are usually based on fibrillar assemblies. In addition to SEM, the gels were characterised by using thermal measurements and circular dichroism spectroscopy. The length of the diamine spacer and the molar ratio of components controlled the self-assembly process by modifying the spatial organisation of the dendritic head groups at the molecular level, which is transcribed into the aspect ratio of the self-assembled state at the microscopic level. Ultimately, this led to diamine-induced control of the macroscopic material's behaviour. When present in excess, the diamine controlled the observed nanoscale morphology as a consequence of undergoing a dendritically controlled nanocrystallisation process to form a network, an unusual and significant result.

Original languageEnglish
Pages (from-to)6552-6559
Number of pages8
JournalChemistry - A European Journal
Volume11
Issue number22
DOIs
Publication statusPublished - 4 Nov 2005

Keywords

  • crystal growth
  • dendrimers
  • gels
  • nanostructures
  • self-assembly
  • 2-COMPONENT DENDRITIC GEL
  • MOLECULAR-MASS GELATORS
  • L-LYSINE
  • ASSOCIATION PROPERTIES
  • AMPHIPHILIC GELATORS
  • AQUEOUS-SOLUTION
  • BUILDING-BLOCKS
  • ETHYLENE-OXIDE
  • ORGANOGELS
  • COPOLYMERS

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