Positron annihilation lifetime spectroscopy (PALS) and small angle x-ray scattering (SAXS) of self-assembled amphiphiles

Aurelia Dong, Carlos Pascual-Izzara, Yao-Da Dong, Steven J Pas, Anita J Hill, Benjamin James Boyd, Calum John Drummond

Research output: Chapter in Book/Report/Conference proceedingConference PaperResearchpeer-review

1 Citation (Scopus)


Self-assembled amphiphile systmes are utilized in a wide variey of applications including drug delivery and energy storage. Nano-scale physical and chemical interactions govern the packing of self-assembled amphiphilic molecules, resulting in thermodynamically stable phases of defined geometries. Possible phases include micellar, hexagonal, cubic, lamellar and sponge phases. The internal nano-structure of the amphiphile self assembly materials play an imprtant role in the properties of these systems and their application. To date small angle x-ray scattering (SAXS) has been the most common technique used to characterise their structure. Positron annihilation lifetime spectroscopy (PALS) offers a possible alernative technique as it is sensitive to both the internal cavities and the intermolecular forces and in combination with SAXS, may provide more detailed structural behaviour of a bulk phytantriol smaple, consisting of 33 w/w water was explored using PALS, and it was found that PALS was sensistive to phase transitions from bicontinous cubic (Pn3m) to reversed hexagonal (H2)to reversed micellar (L2) phases. These boundaries agreed well with SAXS data. Trends observed for the PALS parameters 3 and I3 as a function of tempertaure largely supports the concept that the ortho-positronium in annihilating in the organic regions of the self-assembled structure. However, further investigation is required. We have also developed an innovative data analysis technique to analyse PALS spectra for pore information, with the aim of minimising operator bias and error, which leads to better quantitative comparison of PALS results between laboratories.
Original languageEnglish
Title of host publicationProceedings of SPIE 2007: Microelectronics, MEMS, and Nanotechnology
EditorsHark Hoe Tan, Jung-Chih Chiao, Lorenzo Faraone, Chennupati Jagadish, Jim Williams, Alan R Wilson
Place of PublicationAustralia
Pages1 - 6
Number of pages6
ISBN (Print)9780819469717
Publication statusPublished - 2008
EventSPIE: Microelectronics, MEMS and Nanotechnology 2008 - Canberra, Australia, Australia
Duration: 1 Jan 2008 → …


ConferenceSPIE: Microelectronics, MEMS and Nanotechnology 2008
Period1/01/08 → …

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