Universität zu Köln

Frunza, Stefan, Frunza, Ligia, Ganea, Constantin Paul, Zgura, Irina, Bras, Ana Rita and Schoenhals, Andreas (2016). Rod-like cyanophenyl probe molecules nanoconfined to oxide particles: Density of adsorbed surface species. Eur. Phys. J. Plus, 131 (2). HEIDELBERG: SPRINGER HEIDELBERG. ISSN 2190-5444

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Abstract

Surface layers have already been observed by broadband dielectric spectroscopy for composite systems formed by adsorption of rod-like cyanophenyl derivates as probe molecules on the surface of oxide particles. In this work, features of the surface layer are reported; samples with different amounts of the probe molecules adsorbed onto oxide (nano) particles were prepared in order to study their interactions with the surface. Thermogravimetric analysis (TGA) was applied to analyze the amount of loaded probe molecules. The density of the surface species n(s) was introduced and its values were estimated from quantitative Fourier transform infrared spectroscopy (FTIR) coupled with TGA. This parameter allows discriminating the composites into several groups assuming a similar interaction of the probe molecules with the hosts of a given group. An influence factor H is further proposed as the ratio of the number of molecules in the surface layer showing a glassy dynamics and the number of molecules adsorbed tightly on the surface of the support: It was found for aerosil composites and used for calculating the maximum filling degree of partially filled silica MCM-41 composites showing only one dielectric process characteristic for glass-forming liquids and a bulk behavior for higher filling degrees.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Frunza, Stefan UNSPECIFIED UNSPECIFIED UNSPECIFIED Frunza, Ligia UNSPECIFIED UNSPECIFIED UNSPECIFIED Ganea, Constantin Paul UNSPECIFIED UNSPECIFIED UNSPECIFIED Zgura, Irina UNSPECIFIED UNSPECIFIED UNSPECIFIED Bras, Ana Rita UNSPECIFIED UNSPECIFIED UNSPECIFIED Schoenhals, Andreas UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-284804
DOI:	10.1140/epjp/i2016-16027-5
Journal or Publication Title:	Eur. Phys. J. Plus
Volume:	131
Number:	2
Date:	2016
Publisher:	SPRINGER HEIDELBERG
Place of Publication:	HEIDELBERG
ISSN:	2190-5444
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language LIQUID-CRYSTAL; CHEMICAL FUNCTIONALITY; NANOSCALE CONFINEMENT; DYNAMICS; LAYER; SILICA; NANOCHANNELS; COMPOSITES; FTIR; 4-N-OCTYL-4'-CYANOBIPHENYL Multiple languages Physics, Multidisciplinary Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/28480