Tuning the thermodynamic, optical, and rheological properties of thermoresponsive polymer solutions via silica nanoparticle shape and concentration

Christopher A.p. Neal, Valeria León, Michelle C. Quan, Nondumiso O. Chibambo, Michelle A. Calabrese

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Hypothesis: The shape and quantity of hydrophilic silica nanoparticles (NPs) can be used to tune the microstructure, rheology, and stability of phase-separating polymer solutions. In thermoresponsive polymer systems, silica nanospheres are well-studied whereas anisotropic NPs have little literature precedent. Here, we hypothesize that NP shape and concentration lower the onset of rheological and turbidimetric transitions of aqueous poly(N-isopropyl acrylamide) (PNIPAM) solutions. Experiments: Differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR), turbidimetry, and oscillatory rheology are utilized to examine interactions between NPs, PNIPAM, and water and to track changes in phase separation and rheological properties due to NP concentration and shape. Findings: NP addition reduces phase separation enthalpy due to PNIPAM-NP hydrogen bonding interactions, the degree to which depends on polymer content. While NP addition minorly impacts thermodynamic and optical properties, rheological transitions and associated rheological properties are dramatically altered with increasing temperature, and depend on NP quantity, shape, and polymer molecular weight. Thus NP content and shape can be used to finely tune transition temperatures and mechanical properties for applications in stimuli-responsive materials.

Original languageEnglish (US)
Pages (from-to)878-895
Number of pages18
JournalJournal of Colloid And Interface Science
Volume629
DOIs
StatePublished - Jan 2023

Bibliographical note

Publisher Copyright:
© 2022 Elsevier Inc.

Keywords

  • Differential scanning calorimetry
  • Fourier-transform infrared spectroscopy
  • Hydrogel
  • Lower critical solution temperature
  • Poly(N-isopropyl acrylamide)
  • Rheology
  • Silica nanospheres/nanorods
  • Turbidimetry

MRSEC Support

  • Partial

PubMed: MeSH publication types

  • Journal Article

Fingerprint

Dive into the research topics of 'Tuning the thermodynamic, optical, and rheological properties of thermoresponsive polymer solutions via silica nanoparticle shape and concentration'. Together they form a unique fingerprint.

Cite this