Liquid crystalline behaviour of self-assembled LAPONITE®/PLL–PEG nanocomposites. Issue 15 (19th February 2018)

• Record Type: Journal Article
• Authors: Xu, P.; Lan, Y.; Xing, Z.; Eiser, E.
• Is Part Of: Soft matter. Volume 14:Issue 15(2018)
• Page Start: 2782
• Page End: 2788
• Publication Date: 2018-02-19
• Subjects: Soft condensed matter -- Periodicals; 530.413
• DOI: 10.1039/c7sm01613a
• Languages: English
• ISSNs: 1744-683X

Abstract

Abstract : By coating the flat faces of LAPONITE® disks with the comb-like polymer PLL–PEG we can fully suppress their aging in water and access their liquid-crystalline phases. Abstract : Synthetic LAPONITE®–clay particles with platelet-like shape display strong aging when dispersed in aqueous solutions, preventing the latter from reaching their natural liquid-crystalline equilibrium state. Here we introduce a facile method that successfully prevents this aging behaviour and enables accessing the systems' liquid-crystal and crystalline phases. We graft the comb-like polymer PLL–PEG (poly(l -lysine)- g -poly(ethylene glycol)) onto the clay surfaces from solution, thereby screening the negative surface charges and thus ensuring steric stabilisation. We show zeta-sizer and rheology measurements, respectively, confirming complete steric coating and that aging of dilute samples is completely suppressed even after a year. Using evaporation as a means to concentrate the particles, we observe various liquid crystalline textures under a polarized optical microscope (POM). Upon sequential spreading and drying, we are also able to obtain transparent films with hierarchical architecture.