Journal Article

IMPULSE-2021-00311

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Ternary Nanoswitches Realized with Multiresponsive PMMA‐b‐PNIPMAM Films in Mixed Water/Acetone Vapor Atmospheres

Geiger, C. ; Reitenbach, J. ; Henschel, C. ; Kreuzer, L. P.MLZ* ; Widmann, T. ; Wang, P. ; Mangiapia, G.MLZ* ; Moulin, J.-F.MLZ* ; Papadakis, C. M.MLZ* ; Laschewsky, A. ; Müller-Buschbaum, P. (Corresponding author)MLZ*

2021
Deutsche Gesellschaft für Materialkunde Frankfurt, M.

Please use a persistent id in citations: doi:10.1002/adem.202100191

Abstract: To systematically add functionality to nanoscale polymer switches, an understanding of their responsive behavior is crucial. Herein, solvent vapor stimuli are applied to thin films of a diblock copolymer consisting of a short poly-(methylmethacrylate) (PMMA) block and a long poly-(N-isopropylmethacrylamide) (PNIPMAM) block for realizing ternary nanoswitches. Three significantly distinct film states are successfully implemented by the combination of amphiphilicity and co-nonsolvency effect. The exposure of the thin films to nitrogen, pure water vapor, and mixed water/acetone (90 vol%/10 vol%) vapor switches the films from a dried to a hydrated (solvated and swollen) and a water/acetone-exchanged (solvated and contracted) equilibrium state. These three states have distinctly different film thicknesses and solvent contents, which act as switch positions “off,” “on,” and “standby.” For understanding the switching process, time-of-flight neutron reflectometry (ToF-NR) and spectral reflectance (SR) studies of the swelling and dehydration process are complemented by information on the local solvation of functional groups probed with Fourier-transform infrared (FTIR) spectroscopy. An accelerated responsive behavior beyond a minimum hydration/solvation level is attributed to the fast build-up and depletion of the hydration shell of PNIPMAM, caused by its hydrophobic moieties promoting a cooperative hydration character.

Keyword(s): Chemical Reactions and Advanced Materials (1st) ; Materials Science (2nd) ; Soft Condensed Matter (2nd) ; Condensed Matter Physics (2nd)

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Contributing Institute(s):

1. REFSANS (REFSANS)

Experiment(s):

1. REFSANS: Horizontal TOF Reflectometer with GISANS option (NL2b)

Appears in the scientific report 2021

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Database coverage:
; Clarivate Analytics Master Journal List ; Current Contents - Engineering, Computing and Technology ; DEAL Wiley ; Essential Science Indicators ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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