title: Ionic Strength Responsive Sulfonated Polystyrene Opals.
abstract: Stimuli-responsive photonic crystals (PCs) represent an intriguing class of smart materials very promising for sensing applications. Here, selective ionic strength responsive polymeric PCs are reported. They are easily fabricated by partial sulfonation of polystyrene opals, without using toxic or expensive monomers and etching steps. The color of the resulting hydrogel-like ordered structures can be continuously shifted over the entire visible range (405-760 nm) by changing the content of ions over an extremely wide range of concentration (from about 70 μM to 4 M). The optical response is completely independent from pH and temperature, and the initial color can be fully recovered by washing the sulfonated opals with pure water. These new smart photonic materials could find important applications as ionic strength sensors for environmental monitoring as well as for healthcare screening.
authors.affiliation: The BioRobotics Institute, Scuola Superiore Sant'Anna, Viale Rinaldo Piaggio 34, Pontedera (PI) 56025, Italy.|Center for Micro-BioRobotics @SSSA, Istituto Italiano di Tecnologia , Viale Rinaldo Piaggio 34, Pontedera (PI) 56025, Italy.
authors.forename: Luca
authors.identifier: http://orcid.org/0000-0002-9522-1986
authors.initials: L
authors.lastname: Nucara
authors.affiliation: Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia , P.za San Silvestro 12, Pisa 56127, Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Piazza
authors.affiliation: Center for Micro-BioRobotics @SSSA, Istituto Italiano di Tecnologia , Viale Rinaldo Piaggio 34, Pontedera (PI) 56025, Italy.
authors.forename: Francesco
authors.identifier: http://orcid.org/0000-0003-2899-8389
authors.initials: F
authors.lastname: Greco
authors.affiliation: Department of Physics and Astronomy and London Centre for Nanotechnology, University College London , Gower Street, London WC1E 6BT, United Kingdom.
authors.forename: Valentina
authors.initials: V
authors.lastname: Robbiano
authors.affiliation: Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia , P.za San Silvestro 12, Pisa 56127, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Cappello
authors.affiliation: Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia , P.za San Silvestro 12, Pisa 56127, Italy.
authors.forename: Mauro
authors.initials: M
authors.lastname: Gemmi
authors.affiliation: Department of Physics and Astronomy and London Centre for Nanotechnology, University College London , Gower Street, London WC1E 6BT, United Kingdom.
authors.forename: Franco
authors.initials: F
authors.lastname: Cacialli
authors.affiliation: Center for Micro-BioRobotics @SSSA, Istituto Italiano di Tecnologia , Viale Rinaldo Piaggio 34, Pontedera (PI) 56025, Italy.
authors.forename: Virgilio
authors.identifier: http://orcid.org/0000-0002-4715-8353
authors.initials: V
authors.lastname: Mattoli
keywords: colloids; core−shell particles; ionic strength sensors; polyelectrolytes; stimuli-responsive opals