Ionic Materials for Applications in Sensing and Optoelectronics

Organic salts consist of bulky anions and/or cations whose properties can be tailored for specific purposes. Ionic liquids (ILs) are (semi)organic salts with melting points below 100 ºC. They typically exhibit neglible vapor pressures, high thermal stability, wide liquidus range, and tunable solubility. Moreover specific functions can be built into their respective ions. The first part of the dissertation involves discussions of chiral ionic liquids with additional protic, magnetic, and magneto-luminescent properties, respectively. In addition to their enantioselective sensing capabilities, the ILs may find use in chiral separations and catalysis. The second part of the dissertation involves discussions of fluorescent one-dimensional (1D) nano and microstructures from a group of uniform materials based on organic salts (GUMBOS). These GUMBOS are essentially ‘frozen’ ILs with melting points that range from 25 ºC to 250 ºC. Similar to their liquid ‘cousins’, GUMBOS can be tailored for a variety of applications. Further tunability is obtained through size-confinement effects as a result of the nano (and micro) scale of these materials. The 1D nanomaterials were prepared according to templated and self-assembly methods. In one study a porous alumina membrane was used as a sacrificial template for growing nanotubes, nanowires and nanoarrays from rhodamine 6G tetraphenylborate GUMBOS, [R6G][TPB]. These materials may find possible use in sensing, lasing and waveguiding applications. In another study a series of 1D thiacarbocyanine (TC) GUMBOS nano and microsized structures were obtained by ionic self-assembly through a modified reprecipitation approach. Blended nanomaterials consisting of multiple fluorophores were also prepared, exhibiting Förster Resonance Energy Transfer (FRET). The TC nano and microscale structures offer promise as multicolor-imaging and bioimaging agents, and in (bio)sensing applications

Nontemplated approach to tuning the spectral properties of cyanine-based fluorescent NanoGUMBOS

Template-free controlled aggregation and spectral properties in fluorescent organic nanoparticles (FONs) is highly desirable for various applications. Herein, we report a nontemplated method for controlling the aggregation in near-infrared (NIR) cyanine-based nanoparticles derived from a group of uniform materials based on organic salts (GUMBOS). Cationic heptamethine cyanine dye 1,1′,3,3,3′,3′-hexamethylindotricarbocyanine (HMT) was coupled with five different anions, viz., [NTf2-], [BETI -], [TFPB-], [AOT-], and [TFP4B-], by an ion-exchange method to obtain the respective GUMBOS. The nanoGUMBOS obtained via a reprecipitation method were primarily amorphous and spherical (30-100 nm) as suggested by selected area electron diffraction (SAED) and transmission electron microscopy (TEM). The formation of tunable self-assemblies within the nanoGUMBOS was characterized using absorption and fluorescence spectroscopy in conjunction with molecular dynamics simulations. Counterion-controlled spectral properties observed in the nanoGUMBOS were attributed to variations in J/H ratios with different anions. Association with the [AOT-] anion afforded predominant J aggregation enabling the highest fluorescence intensity, whereas [TFP4B-] disabled the fluorescence due to predominant H aggregation in the nanoparticles. Analyses of the stacking angle of the cations based on molecular dynamic simulation results in [HMT][NTf2], [HMT][BETI], and [HMT][AOT] dispersed in water and a visual analysis of the representative simulation snapshots also imply that the type of aggregation was controlled through the counterion associated with the dye cation. © 2010 American Chemical Society

Predicting attitudinal and behavioral responses to COVID-19 pandemic using machine learning

At the beginning of 2020, COVID-19 became a global problem. Despite all the efforts to emphasize the relevance of preventive measures, not everyone adhered to them. Thus, learning more about the characteristics determining attitudinal and behavioral responses to the pandemic is crucial to improving future interventions. In this study, we applied machine learning on the multi-national data collected by the International Collaboration on the Social and Moral Psychology of COVID-19 (N = 51,404) to test the predictive efficacy of constructs from social, moral, cognitive, and personality psychology, as well as socio-demographic factors, in the attitudinal and behavioral responses to the pandemic. The results point to several valuable insights. Internalized moral identity provided the most consistent predictive contribution—individuals perceiving moral traits as central to their self-concept reported higher adherence to preventive measures. Similar was found for morality as cooperation, symbolized moral identity, self-control, open-mindedness, collective narcissism, while the inverse relationship was evident for the endorsement of conspiracy theories. However, we also found a non-negligible variability in the explained variance and predictive contributions with respect to macro-level factors such as the pandemic stage or cultural region. Overall, the results underscore the importance of morality-related and contextual factors in understanding adherence to public health recommendations during the pandemic.Peer reviewe

National identity predicts public health support during a global pandemic

Changing collective behaviour and supporting non-pharmaceutical interventions is an important component in mitigating virus transmission during a pandemic. In a large international collaboration (Study 1, N = 49,968 across 67 countries), we investigated self-reported factors associated with public health behaviours (e.g., spatial distancing and stricter hygiene) and endorsed public policy interventions (e.g., closing bars and restaurants) during the early stage of the COVID-19 pandemic (April-May 2020). Respondents who reported identifying more strongly with their nation consistently reported greater engagement in public health behaviours and support for public health policies. Results were similar for representative and non-representative national samples. Study 2 (N = 42 countries) conceptually replicated the central finding using aggregate indices of national identity (obtained using the World Values Survey) and a measure of actual behaviour change during the pandemic (obtained from Google mobility reports). Higher levels of national identification prior to the pandemic predicted lower mobility during the early stage of the pandemic (r = −0.40). We discuss the potential implications of links between national identity, leadership, and public health for managing COVID-19 and future pandemics.publishedVersio

National identity predicts public health support during a global pandemic.

Changing collective behaviour and supporting non-pharmaceutical interventions is an important component in mitigating virus transmission during a pandemic. In a large international collaboration (Study 1, N = 49,968 across 67 countries), we investigated self-reported factors associated with public health behaviours (e.g., spatial distancing and stricter hygiene) and endorsed public policy interventions (e.g., closing bars and restaurants) during the early stage of the COVID-19 pandemic (April-May 2020). Respondents who reported identifying more strongly with their nation consistently reported greater engagement in public health behaviours and support for public health policies. Results were similar for representative and non-representative national samples. Study 2 (N = 42 countries) conceptually replicated the central finding using aggregate indices of national identity (obtained using the World Values Survey) and a measure of actual behaviour change during the pandemic (obtained from Google mobility reports). Higher levels of national identification prior to the pandemic predicted lower mobility during the early stage of the pandemic (r = -0.40). We discuss the potential implications of links between national identity, leadership, and public health for managing COVID-19 and future pandemics

National identity predicts public health support during a global pandemic (vol 13, 517, 2022) : National identity predicts public health support during a global pandemic (Nature Communications, (2022), 13, 1, (517), 10.1038/s41467-021-27668-9)

Publisher Copyright: © The Author(s) 2022.In this article the author name ‘Agustin Ibanez’ was incorrectly written as ‘Augustin Ibanez’. The original article has been corrected.Peer reviewe

Predicting attitudinal and behavioral responses to COVID-19 pandemic using machine learning

At the beginning of 2020, COVID-19 became a global problem. Despite all the efforts to emphasize the relevance of preventive measures, not everyone adhered to them. Thus, learning more about the characteristics determining attitudinal and behavioral responses to the pandemic is crucial to improving future interventions. In this study, we applied machine learning on the multinational data collected by the International Collaboration on the Social and Moral Psychology of COVID-19 (N = 51,404) to test the predictive efficacy of constructs from social, moral, cognitive, and personality psychology, as well as socio-demographic factors, in the attitudinal and behavioral responses to the pandemic. The results point to several valuable insights. Internalized moral identity provided the most consistent predictive contribution—individuals perceiving moral traits as central to their self-concept reported higher adherence to preventive measures. Similar results were found for morality as cooperation, symbolized moral identity, self-control, open-mindedness, and collective narcissism, while the inverse relationship was evident for the endorsement of conspiracy theories. However, we also found a non-neglible variability in the explained variance and predictive contributions with respect to macro-level factors such as the pandemic stage or cultural region. Overall, the results underscore the importance of morality-related and contextual factors in understanding adherence to public health recommendations during the pandemic

Author Correction: National identity predicts public health support during a global pandemic

Correction to: Nature Communications https://doi.org/10.1038/s41467-021-27668-9, published online 26 January 2022

Highly efficient extraction of phenols from aqueous solution using magnetic room temperature ionic liquids

Water-insoluble magnetic room temperature ionic liquid (MRTIL), [3C 6PC14][FeCl4], was synthesized from trihexyltetradecylphosphonium chloride and FeCl3·6H 2O. The MRTIL was used for solvent extraction of phenols from aqueous solution. Due to its strong paramagneticity, [3C6PC 14][FeCl4] can respond to an external magnetic field, which was employed to design a novel magnetic extraction technique. Extraction conditions such as extraction time, volume ratio between MRTIL and aqueous phase, and pH were optimized. Phenols with multiple chlorine substituents exhibited higher distribution ratios. Compared with four traditional non-magnetic ionic liquids, the MRTIL exhibited significantly higher extraction efficiency. ©The Electrochemical Society