TY  - JOUR
A1  - Wagner, Tom
A1  - Oded, Meirav
A1  - Shenhar, Roy
A1  - Böker, Alexander
T1  - Two-dimensionally ordered AuNP array formation via microcontact printing on lamellar diblock copolymer films
JF  - Polymers for advanced technologies
N2  - The construction of nano-sized, two-dimensionally ordered nanoparticle (NP) superstructures is important for various advanced applications such as photonics, sensing, catalysis, or nano-circuitry. Currently, such structures are fabricated using the templated organization approach, in which the templates are mainly created by photo-lithography or laser-lithography and other invasive top-down etching procedures. In this work, we present an alternative bottom-up preparation method for the controlled deposition of NPs into hierarchical structures. Lamellar polystyrene-block-poly(2-vinylpyridinium) thin films featuring alternating stripes of neutral PS and positively charged P2VP domains serve as templates, allowing for the selective adsorption of negatively charged gold NPs. Dense NP assembly is achieved by a simple immersion process, whereas two-dimensionally ordered arrays of NPs are realized by microcontact printing (mu CP), utilizing periodic polydimethylsiloxane wrinkle grooves loaded with gold NPs. This approach enables the facile construction of hierarchical NP arrays with variable geometries. Copyright (C) 2016 John Wiley & Sons, Ltd.
KW  - block copolymers
KW  - electrostatic assembly
KW  - microcontact printing
KW  - gold nanoparticles
Y1  - 2017
U6  - https://doi.org/10.1002/pat.3853
SN  - 1042-7147
SN  - 1099-1581
VL  - 28
SP  - 623
EP  - 628
PB  - Wiley
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Wagner, Tom
A1  - Lazar, Jaroslav
A1  - Schnakenberg, Uwe
A1  - Böker, Alexander
T1  - In situ Electrothemical Impedance Spectroscopy of Electrostatically Driven Selective Gold Nanoparticle Adsorption on Block Copolymer Lamellae
JF  - Trials
N2  - Electrostatic attraction between charged nano particles and oppositely charged nanopatterned polymeric films enables tailored structuring of functional nanoscopic surfaces. The bottom-up fabrication of organic/inorganic composites for example bears promising potential toward cheap fabrication of catalysts, optical sensors, and the manufacture of miniaturized electric circuitry. However, only little is known about the time-dependent adsorption behavior and the electronic or ionic charge transfer in the film bulk and at interfaces during nanoparticle assembly via electrostatic interactions. In situ electrochemical impedance spectroscopy (EIS) in combination with a microfluidic system for fast and reproducible liquid delivery was thus applied to monitor the selective deposition of negatively charged gold nanoparticles on top of positively charged poly(2-vinylpyridinium) (qP2VP) domains of phase separated lamellar poly(styrene)-block-poly(2-vinylpyridinium) (PS-b-qP2VP) diblock copolymer thin films. The acquired impedance data delivered information with respect to interfacial charge alteration, ionic diffusion, and the charge dependent nanoparticle adsorption kinetics, considering this yet unexplored system. We demonstrate that the selective adsorption of negatively charged gold nanoparticles (AuNPs) on positively charged qP2VP domains of lamellar PS-b-qP2VP thin films can indeed be tracked by EIS. Moreover, we show that the nanoparticle adsorption kinetics and the nanoparticle packing density are functions of the charge density in the qP2VP domains.
KW  - impedance spectroscopy
KW  - block copolymers
KW  - nanoparticles
KW  - electrostatics
KW  - adsorption kinetics
Y1  - 2016
U6  - https://doi.org/10.1021/acsami.6b07708
SN  - 1944-8244
VL  - 8
SP  - 27282
EP  - 27290
PB  - American Chemical Society
CY  - Washington
ER  -