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Quest for Thermoresponsive Block Copolymer Nanoparticles with Liquid–Crystalline Surfactant Cores
[Image: see text] This work reports on the preparation and characterization of anisotropic composition nanoparticles based on the electrostatic binding of dodecyltrimethylammonium surfactant to poly(acrylic acid) blocks of diblock copolymers with poly(ethylene oxide) (PEO) and poly(N-isopropyl acryl...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Chemical Society
2017
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6644550/ https://www.ncbi.nlm.nih.gov/pubmed/31457819 http://dx.doi.org/10.1021/acsomega.7b00905 |
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author | Carneiro, Nathalia M. Percebom, Ana M. Loh, Watson |
author_facet | Carneiro, Nathalia M. Percebom, Ana M. Loh, Watson |
author_sort | Carneiro, Nathalia M. |
collection | PubMed |
description | [Image: see text] This work reports on the preparation and characterization of anisotropic composition nanoparticles based on the electrostatic binding of dodecyltrimethylammonium surfactant to poly(acrylic acid) blocks of diblock copolymers with poly(ethylene oxide) (PEO) and poly(N-isopropyl acrylamide) (PNIPAm). These nanoparticles form kinetically stable dispersions and display liquid–crystalline cores with a micellar cubic structure, as determined by small-angle X-ray scattering. Mixtures with different proportions of the two block copolymers and stoichiometric amounts of C(12)TA(+) were prepared and their behavior was compared with that of the parent nanoparticles. Upon heating, dilute dispersions (0.01 and 0.1 wt %) analyzed by dynamic light scattering display a slight decrease in the hydrodynamic radius, consistent with the dehydration of PNIPAm and mixed PNIPAm–PEO blocks at the shell. At higher concentrations, 2 wt %, the nanoparticles with pure PNIPAm shell undergo macroscopic phase separation above 32 °C. Nanoparticles with a pure PEO shell do not display temperature sensitivity. For the mixtures, no visual change is observed, but the dynamic light scattering results evidence the formation of clusters, whose size and reversibility depend on the PEO/PNIPAm proportion. This indicates the formation of mixed nanoparticles containing both PEO and PNIPAm blocks. Nuclear Overhauser enhancement spectroscopy NMR analyses of the mixtures do not show the correlation peak expected for PEO and PNIPAm blocks in close proximity, suggesting their segregation at the nanoparticle shell. On the basis of these results, we discuss the possibilities of the neutral blocks distribution on the shell of mixed nanoparticles. Overall, we have confirmed that these nanoparticles may display a temperature-controlled reversible aggregation while preserving their internal liquid–crystalline structures. |
format | Online Article Text |
id | pubmed-6644550 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2017 |
publisher | American Chemical Society |
record_format | MEDLINE/PubMed |
spelling | pubmed-66445502019-08-27 Quest for Thermoresponsive Block Copolymer Nanoparticles with Liquid–Crystalline Surfactant Cores Carneiro, Nathalia M. Percebom, Ana M. Loh, Watson ACS Omega [Image: see text] This work reports on the preparation and characterization of anisotropic composition nanoparticles based on the electrostatic binding of dodecyltrimethylammonium surfactant to poly(acrylic acid) blocks of diblock copolymers with poly(ethylene oxide) (PEO) and poly(N-isopropyl acrylamide) (PNIPAm). These nanoparticles form kinetically stable dispersions and display liquid–crystalline cores with a micellar cubic structure, as determined by small-angle X-ray scattering. Mixtures with different proportions of the two block copolymers and stoichiometric amounts of C(12)TA(+) were prepared and their behavior was compared with that of the parent nanoparticles. Upon heating, dilute dispersions (0.01 and 0.1 wt %) analyzed by dynamic light scattering display a slight decrease in the hydrodynamic radius, consistent with the dehydration of PNIPAm and mixed PNIPAm–PEO blocks at the shell. At higher concentrations, 2 wt %, the nanoparticles with pure PNIPAm shell undergo macroscopic phase separation above 32 °C. Nanoparticles with a pure PEO shell do not display temperature sensitivity. For the mixtures, no visual change is observed, but the dynamic light scattering results evidence the formation of clusters, whose size and reversibility depend on the PEO/PNIPAm proportion. This indicates the formation of mixed nanoparticles containing both PEO and PNIPAm blocks. Nuclear Overhauser enhancement spectroscopy NMR analyses of the mixtures do not show the correlation peak expected for PEO and PNIPAm blocks in close proximity, suggesting their segregation at the nanoparticle shell. On the basis of these results, we discuss the possibilities of the neutral blocks distribution on the shell of mixed nanoparticles. Overall, we have confirmed that these nanoparticles may display a temperature-controlled reversible aggregation while preserving their internal liquid–crystalline structures. American Chemical Society 2017-09-06 /pmc/articles/PMC6644550/ /pubmed/31457819 http://dx.doi.org/10.1021/acsomega.7b00905 Text en Copyright © 2017 American Chemical Society This is an open access article published under an ACS AuthorChoice License (http://pubs.acs.org/page/policy/authorchoice_termsofuse.html) , which permits copying and redistribution of the article or any adaptations for non-commercial purposes. |
spellingShingle | Carneiro, Nathalia M. Percebom, Ana M. Loh, Watson Quest for Thermoresponsive Block Copolymer Nanoparticles with Liquid–Crystalline Surfactant Cores |
title | Quest for Thermoresponsive Block Copolymer Nanoparticles
with Liquid–Crystalline Surfactant Cores |
title_full | Quest for Thermoresponsive Block Copolymer Nanoparticles
with Liquid–Crystalline Surfactant Cores |
title_fullStr | Quest for Thermoresponsive Block Copolymer Nanoparticles
with Liquid–Crystalline Surfactant Cores |
title_full_unstemmed | Quest for Thermoresponsive Block Copolymer Nanoparticles
with Liquid–Crystalline Surfactant Cores |
title_short | Quest for Thermoresponsive Block Copolymer Nanoparticles
with Liquid–Crystalline Surfactant Cores |
title_sort | quest for thermoresponsive block copolymer nanoparticles
with liquid–crystalline surfactant cores |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6644550/ https://www.ncbi.nlm.nih.gov/pubmed/31457819 http://dx.doi.org/10.1021/acsomega.7b00905 |
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