X-ray reflectivity analysis of thin complex Langmuir-Blodgett
films

J 2001

X-ray reflectivity analysis of thin complex Langmuir-Blodgett films

POLOUČEK, Pavel, U. PIETSCH, T. GEUE, C. SYMIETZ, G. BREZESINSKI et. al.

Basic information

Original name

X-ray reflectivity analysis of thin complex Langmuir-Blodgett films

Name in Czech

Analýza tenkých složitých Langmuir-Blodgettových filmů rtg reflektivitou

Authors

POLOUČEK, Pavel (203 Czech Republic, guarantor), U. PIETSCH (276 Germany), T. GEUE (276 Germany), C. SYMIETZ (276 Germany) and G. BREZESINSKI (276 Germany)

Edition

Journal of physics D: Applied physics, Bristol, England, IOP Publishing Ltd. 2001, 0022-3727

Other information

Language

English

Type of outcome

Článek v odborném periodiku

Field of Study

10302 Condensed matter physics

Country of publisher

United Kingdom of Great Britain and Northern Ireland

Confidentiality degree

není předmětem státního či obchodního tajemství

Impact factor

Impact factor: 1.260

RIV identification code

RIV/00216224:14310/01:00021638

Organization unit

Faculty of Science

UT WoS

000167349700002

Keywords in English

x-ray reflectivity; xrr; thin film; langmuir-blodgett films; density

Abstract

ORIG CZ

V originále

Using specular x ray reflectivity, we have examined the vertical structure of charge coupled polyelectrolyte (PDADMAC)-lipid (DPPA) films on the water surface and on a silicon substrate, prepared by means of the Langmuir-Blodgett technique. The complicated structure of these films, characterized by electron density variations on the sub nanometre scale and low density contrast between sub layers, causes failure of the standard box model fitting method-it yields poor matching to data and/or ambiguous density profiles. We show that this problem can be overcome utilizing a different, model free fitting method, which yields perfect fits and less ambiguous electron density profiles for all investigated films. The ambiguity of results can be further reduced when the sets of possible density profiles obtained for several similar samples are compared to each other. Discussing the model free fitting method in detail along with general questions of reflectivity data evaluation, we aim to give practical instructions for the structure analysis of thin organic films. The obtained density profiles, being in good agreement with the structure model based on previous diffraction experiments, reveal some new details: The DPPA's phosphate head groups penetrate inside the PDADMAC helix rather than being bound onto its surface. The structure remains almost unchanged after transferring one layer onto Si wafer, but subsequently transferred layers exhibit decreasing order.

In Czech

Metoda rtg reflektivity byla použita pro studium struktury Langmuir-Blodgettových filmů na bázi PDADMAC - lipid (DPPA).

Links

MSM 143100002, plan (intention)

Name: Fyzikální vlastnosti nových materiálů a vrstevnatých struktur

Investor: Ministry of Education, Youth and Sports of the CR, Physical properties of new materials and layered structures

Citovat

POLOUČEK, Pavel, U. PIETSCH, T. GEUE, C. SYMIETZ and G. BREZESINSKI. X-ray reflectivity analysis of thin complex Langmuir-Blodgett films. Journal of physics D: Applied physics. Bristol, England: IOP Publishing Ltd., 2001, vol. 34, No 4, p. 450-458. ISSN 0022-3727.

@article{630745,
   author = {Polouček, Pavel and Pietsch, U. and Geue, T. and Symietz, C. and Brezesinski, G.},
   article_location = {Bristol, England},
   article_number = {4},
   keywords = {x-ray reflectivity; xrr; thin film; langmuir-blodgett films; density},
   language = {eng},
   issn = {0022-3727},
   journal = {Journal of physics D: Applied physics},
   title = {X-ray reflectivity analysis of thin complex Langmuir-Blodgett films},
   volume = {34},
   year = {2001}
}

TY  - JOUR
ID  - 630745
AU  - Polouček, Pavel - Pietsch, U. - Geue, T. - Symietz, C. - Brezesinski, G.
PY  - 2001
TI  - X-ray reflectivity analysis of thin complex Langmuir-Blodgett films
JF  - Journal of physics D: Applied physics
VL  - 34
IS  - 4
SP  - 450-458
EP  - 450-458
PB  - IOP Publishing Ltd.
SN  - 00223727
KW  - x-ray reflectivity
KW  - xrr
KW  - thin film
KW  - langmuir-blodgett films
KW  - density
N2  - Using specular x ray reflectivity, we have examined the vertical structure of charge coupled polyelectrolyte (PDADMAC)-lipid (DPPA) films on the water surface and on a silicon substrate, prepared by means of the Langmuir-Blodgett technique. The complicated structure of these films, characterized by electron density variations on the sub nanometre scale and low density contrast between sub layers, causes failure of the standard box model fitting method-it yields poor matching to data and/or ambiguous density profiles. We show that this problem can be overcome utilizing a different, model free fitting method, which yields perfect fits and less ambiguous electron density profiles for all investigated films. The ambiguity of results can be further reduced when the sets of possible density profiles obtained for several similar samples are compared to each other. Discussing the model free fitting method in detail along with general questions of reflectivity data evaluation, we aim to give practical instructions for the structure analysis of thin organic films. The obtained density profiles, being in good agreement with the structure model based on previous diffraction experiments, reveal some new details: The DPPA's phosphate head groups penetrate inside the PDADMAC helix rather than being bound onto its surface. The structure remains almost unchanged after transferring one layer onto Si wafer, but subsequently transferred layers exhibit decreasing order.
ER  -

POLOUČEK, Pavel, U. PIETSCH, T. GEUE, C. SYMIETZ and G. BREZESINSKI. X-ray reflectivity analysis of thin complex Langmuir-Blodgett films. \textit{Journal of physics D: Applied physics}. Bristol, England: IOP Publishing Ltd., 2001, vol.~34, No~4, p.~450-458. ISSN~0022-3727.

Detailed Information on Publication Record