Title: Multi-stimuli responsive tetra-PPO₆₀-PEO₂₀ ethylene diamine block copolymer enables pH, temperature, and solvent regulation of Au nanoparticle composite plasmonic response

Abstract

In this work a gold nanoparticle (NP) hydrogel composite prepared by multi-step cascade synthesis undergoes temperature, pH, and solvent dependent nanoscale structural transformations promoting modulation of the plasmon resonance. The composite is spontaneously prepared from a non-covalent lamellar structured lyotropic mesophase (complex fluid) composed of amphiphiles (DMPC and Triton X-100) that support the reactive constituents, a mixture of hydroxyl and acrylate end-derivatized Tetronic (Poloxamine) polymer and [AuCl4]^–. The reaction sequence begins with the reduction of [AuCl4]^– by the ethylene diamine linkage and PEO blocks of the Tetronic, yielding Au NPs. The redox reaction generates free radicals initiating crosslinking of the acrylate end-derivatized polymer producing a chemical hydrogel. Optical spectroscopy and electron microscopy confirm Au NP formation. ATR/FT-IR spectroscopy and thermal analysis establish acrylate crosslinking and network formation. X-ray scattering reveals the composite reversibly converts between multilamellar and bicontinuous cubic structures as temperature is increased above 35 °C for composites containing protonated ethylene diamine linkages (un-buffered water or acidic buffer). The reversible changes in nanoarchitecture red shifts and broadens the collective plasmon (from 523 nm to 575 nm) of the composite, an observation attributed to re-organization of confined NPs from 2D sheets (lamellae) to 1D columns (bicontinuous cubic channels). Composites preparedmore » in alkaline buffer do not undergo a structural conversion with temperature, retaining a multilamellar architecture. In addition to pH and thermo-responsivity, the composite swells reversibly in polar solvents, which acts to de-aggregate and aggregate the encapsulated NPs and varies the plasmon resonance by Δ52 nm. This work reports the first combined use of a polymer to achieve both the in situ synthesis of spatially confined plasmonic NPs and their reversible stimuli-triggered re-organization mediated by interconvertible changes in scaffold nanoarchitecture.« less

Authors:

Diouf, Sokhna Issa-Yacine Faye ^[1]; Williams, Darrick Joseph  ^[1];

• Search DOE PAGES for author "Williams, Darrick Joseph"
• Search DOE PAGES for ORCID "0000-0002-3943-4696"

Seifert, Sönke ^[2]; Londoño-Calderon, Alejandra  ^[1];

• Search DOE PAGES for author "Londoño-Calderon, Alejandra"
• Search DOE PAGES for ORCID "0000-0002-0277-3571"

Pettes, Michael T.  ^[1];

• Search DOE PAGES for author "Pettes, Michael T."
• Search DOE PAGES for ORCID "0000-0001-6862-6841"

Sheehan, Christopher J. ^[1]; Firestone, Millicent Anne  ^[1]

• Search DOE PAGES for author "Firestone, Millicent Anne"
• Search DOE PAGES for ORCID "0000-0002-8671-1502"

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+ Show Author Affiliations

1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2. Argonne National Lab. (ANL), Lemont, IL (United States)

Publication Date:

Mon Nov 04 00:00:00 EST 2019

Research Org.:

Argonne National Laboratory (ANL), Argonne, IL (United States). Advanced Photon Source (APS); Los Alamos National Laboratory (LANL), Los Alamos, NM (United States). Center for Integrated Nanotechnologies (CINT)

Sponsoring Org.:

USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1615497

Alternate Identifier(s):

OSTI ID: 1576846; OSTI ID: 1634969

Report Number(s):

LA-UR-19-29838
Journal ID: ISSN 1759-9954; PCOHC2; 159360

Grant/Contract Number:  

AC02-06CH11357; 89233218CNA000001

Resource Type:

Accepted Manuscript

Journal Name:

Polymer Chemistry

Additional Journal Information:

Journal Volume: 10; Journal Issue: 47; Journal ID: ISSN 1759-9954

Publisher:

Royal Society of Chemistry

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Material Science