Thermally-induced softening of PNIPAm-based nanopillar arrays
The surface properties of soft nanostructured hydrogels are crucial in the design of responsive materials that can be used as platforms to create adaptive devices. The lower critical solution temperature (LCST) of thermo-responsive hydrogels such as poly(N-isopropylacrylamide) (PNIPAm) can be modifi...
Guardado en:
| Autor principal: | |
|---|---|
| Publicado: |
2017
|
| Materias: | |
| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_1744683X_v13_n13_p2453_Sanz http://hdl.handle.net/20.500.12110/paper_1744683X_v13_n13_p2453_Sanz |
| Aporte de: |
| id |
paper:paper_1744683X_v13_n13_p2453_Sanz |
|---|---|
| record_format |
dspace |
| spelling |
paper:paper_1744683X_v13_n13_p2453_Sanz2025-07-30T19:03:51Z Thermally-induced softening of PNIPAm-based nanopillar arrays von Bilderling, Catalina Acrylic monomers Amides Atom transfer radical polymerization Atomic force microscopy Contact angle Free radical reactions Hydrogels Hydrophilicity Mechanical properties Molecular dynamics Monomers Nanosystems Stiffness Topology Anodized aluminum oxide Hydrophilic/hydrophobic Lower critical solution temperature Molecular dynamics simulations Nanostructured hydrogels Poly(N-isopropyl acrylamide) (pNIPAM) Thermo-responsive hydrogels Topological characteristics Nanostructures The surface properties of soft nanostructured hydrogels are crucial in the design of responsive materials that can be used as platforms to create adaptive devices. The lower critical solution temperature (LCST) of thermo-responsive hydrogels such as poly(N-isopropylacrylamide) (PNIPAm) can be modified by introducing a hydrophilic monomer to create a wide range of thermo-responsive micro-/nano-structures in a large temperature range. Using surface initiation atom-transfer radical polymerization in synthesized anodized aluminum oxide templates, we designed, fabricated, and characterized thermo-responsive nanopillars based on PNIPAm hydrogels with tunable mechanical properties by incorporating acrylamide monomers (AAm). In addition to their LCST, the incorporation of a hydrophilic entity in the nanopillars based on PNIPAm has abruptly changed the topological and mechanical properties of our system. To gain an insight into the mechanical properties of the nanostructure, its hydrophilic/hydrophobic behavior and topological characteristics, atomic force microscopy, molecular dynamics simulations and water contact angle studies were combined. When changing the nanopillar composition, a significant and opposite variation was observed in their mechanical properties. As temperature increased above the LCST, the stiffness of PNIPAm nanopillars, as expected, did so too, in contrast to the stiffness of PNIPAm-AAm nanopillars that decreased significantly. The molecular dynamics simulations proposed a local molecular rearrangement in our nanosystems at the LCST. The local aggregation of NIPAm segments near the center of the nanopillars displaced the hydrophilic AAm units towards the surface of the structure leading to contact with the aqueous environment. This behavior was confirmed via contact angle measurements below and above the LCST. © The Royal Society of Chemistry. Fil:Von Bilderling, C. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2017 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_1744683X_v13_n13_p2453_Sanz http://hdl.handle.net/20.500.12110/paper_1744683X_v13_n13_p2453_Sanz |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Acrylic monomers Amides Atom transfer radical polymerization Atomic force microscopy Contact angle Free radical reactions Hydrogels Hydrophilicity Mechanical properties Molecular dynamics Monomers Nanosystems Stiffness Topology Anodized aluminum oxide Hydrophilic/hydrophobic Lower critical solution temperature Molecular dynamics simulations Nanostructured hydrogels Poly(N-isopropyl acrylamide) (pNIPAM) Thermo-responsive hydrogels Topological characteristics Nanostructures |
| spellingShingle |
Acrylic monomers Amides Atom transfer radical polymerization Atomic force microscopy Contact angle Free radical reactions Hydrogels Hydrophilicity Mechanical properties Molecular dynamics Monomers Nanosystems Stiffness Topology Anodized aluminum oxide Hydrophilic/hydrophobic Lower critical solution temperature Molecular dynamics simulations Nanostructured hydrogels Poly(N-isopropyl acrylamide) (pNIPAM) Thermo-responsive hydrogels Topological characteristics Nanostructures von Bilderling, Catalina Thermally-induced softening of PNIPAm-based nanopillar arrays |
| topic_facet |
Acrylic monomers Amides Atom transfer radical polymerization Atomic force microscopy Contact angle Free radical reactions Hydrogels Hydrophilicity Mechanical properties Molecular dynamics Monomers Nanosystems Stiffness Topology Anodized aluminum oxide Hydrophilic/hydrophobic Lower critical solution temperature Molecular dynamics simulations Nanostructured hydrogels Poly(N-isopropyl acrylamide) (pNIPAM) Thermo-responsive hydrogels Topological characteristics Nanostructures |
| description |
The surface properties of soft nanostructured hydrogels are crucial in the design of responsive materials that can be used as platforms to create adaptive devices. The lower critical solution temperature (LCST) of thermo-responsive hydrogels such as poly(N-isopropylacrylamide) (PNIPAm) can be modified by introducing a hydrophilic monomer to create a wide range of thermo-responsive micro-/nano-structures in a large temperature range. Using surface initiation atom-transfer radical polymerization in synthesized anodized aluminum oxide templates, we designed, fabricated, and characterized thermo-responsive nanopillars based on PNIPAm hydrogels with tunable mechanical properties by incorporating acrylamide monomers (AAm). In addition to their LCST, the incorporation of a hydrophilic entity in the nanopillars based on PNIPAm has abruptly changed the topological and mechanical properties of our system. To gain an insight into the mechanical properties of the nanostructure, its hydrophilic/hydrophobic behavior and topological characteristics, atomic force microscopy, molecular dynamics simulations and water contact angle studies were combined. When changing the nanopillar composition, a significant and opposite variation was observed in their mechanical properties. As temperature increased above the LCST, the stiffness of PNIPAm nanopillars, as expected, did so too, in contrast to the stiffness of PNIPAm-AAm nanopillars that decreased significantly. The molecular dynamics simulations proposed a local molecular rearrangement in our nanosystems at the LCST. The local aggregation of NIPAm segments near the center of the nanopillars displaced the hydrophilic AAm units towards the surface of the structure leading to contact with the aqueous environment. This behavior was confirmed via contact angle measurements below and above the LCST. © The Royal Society of Chemistry. |
| author |
von Bilderling, Catalina |
| author_facet |
von Bilderling, Catalina |
| author_sort |
von Bilderling, Catalina |
| title |
Thermally-induced softening of PNIPAm-based nanopillar arrays |
| title_short |
Thermally-induced softening of PNIPAm-based nanopillar arrays |
| title_full |
Thermally-induced softening of PNIPAm-based nanopillar arrays |
| title_fullStr |
Thermally-induced softening of PNIPAm-based nanopillar arrays |
| title_full_unstemmed |
Thermally-induced softening of PNIPAm-based nanopillar arrays |
| title_sort |
thermally-induced softening of pnipam-based nanopillar arrays |
| publishDate |
2017 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_1744683X_v13_n13_p2453_Sanz http://hdl.handle.net/20.500.12110/paper_1744683X_v13_n13_p2453_Sanz |
| work_keys_str_mv |
AT vonbilderlingcatalina thermallyinducedsofteningofpnipambasednanopillararrays |
| _version_ |
1840325966244610048 |