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

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

doi:10.1016/j.jcis.2022.08.139

Cited by 4 publications

(26 citation statements)

References 115 publications

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“…[ 60,66–69 ] Additionally, A 8 NP‐containing PNIPAM solutions provide good modulus enhancement upon temperature elevation, and are also colloidally stable and less prone to settling in dilute polymer solutions than higher 𝐴 NPs. [ 56 ] Supplementary experiments utilizing longer NPs ( A 14) with similar surface properties [ 56 ] and spherical NPs ( 𝐴 1) are used to further strengthen the findings (SI.25). Using a combination of Fourier‐transform infrared spectroscopy (FTIR), magnetoturbidimetry, differential scanning calorimetry (DSC), and magneto‐rheology, the solution behavior of PNIPAM is examined in the presence of magnetic fields, NPs, and both magnetic fields and NPs to determine how polymer–solvent interactions are altered to impact the thermoresponsivity.…”

Section: Introductionmentioning

confidence: 87%

“…[ 55,61,62 ] Beyond altering PNIPAM‐water hydrogen bonding, NP addition can increase physical network connectivity following phase separation, increasing mechanical properties such as viscosity and dynamic moduli. [ 56,63–65 ]…”

Section: Introductionmentioning

confidence: 99%

“…[ 56 ] In this regime, NP curvature is inconsequential and changes in Δ H sep and Fourier transform infrared spectroscopy (FTIR) signatures with NP aspect ratio can be explained by normalizing to the total NP surface area, and by accounting for differences in NP 𝜁 ‐potential (zeta‐potential) caused by changes in surface silanol density. [ 56 ] At high NP aspect ratio ( 𝐴 8, 𝐴 14), NP‐containing solutions had the highest colloidal stability (highest magnitude 𝜁 −‐ potential) and NP surface properties such as surface silanol density and mesoporosity were virtually independent of NP aspect ratio. [ 56 ] Interestingly, despite small changes in thermodynamics, significant differences in the rheological behavior of PNIPAM‐NP solutions were observed with NP aspect ratio.…”

Section: Introductionmentioning

confidence: 99%

“…[ 56 ] At high NP aspect ratio ( 𝐴 8, 𝐴 14), NP‐containing solutions had the highest colloidal stability (highest magnitude 𝜁 −‐ potential) and NP surface properties such as surface silanol density and mesoporosity were virtually independent of NP aspect ratio. [ 56 ] Interestingly, despite small changes in thermodynamics, significant differences in the rheological behavior of PNIPAM‐NP solutions were observed with NP aspect ratio. Here, longer NPs led to higher dynamic moduli as the temperature increased above the onset of transition.…”

Section: Introductionmentioning

confidence: 99%

“…Here, longer NPs led to higher dynamic moduli as the temperature increased above the onset of transition. [ 56 ]…”

Section: Introductionmentioning

confidence: 99%

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Effect of nanoparticle loading and magnetic field application on the thermodynamic, optical, and rheological behavior of thermoresponsive polymer solutions

Neal

Kresge

Quan

et al. 2022

Vinyl Additive Technology

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Although processing via external stimuli is a promising technique to tune the structure and properties of polymeric materials, the impact of magnetic fields on phase transitions in thermoresponsive polymer solutions is not well-understood. As nanoparticle (NP) addition is also known to impact these thermodynamic and optical properties, synergistic effects from combining magnetic fields with NP incorporation provide a novel route for tuning material properties. Here, the thermodynamic, optical, and rheological properties of aqueous poly(N-isopropyl acrylamide) (PNIPAM) solutions are examined in the presence of hydrophilic silica NPs and magnetic fields, individually and jointly, via Fourier-transform infrared spectroscopy (FTIR), magneto-turbidimetry, differential scanning calorimetry (DSC), and magneto-rheology. While NPs and magnetic fields both reduce the phase separation energy barrier and lower optical transition temperatures by altering hydrogen bonding (H-bonding), infrared spectra demonstrate that the mechanism by which these changes occur is distinct. Magnetic fields primarily alter solvent polarization while NPs provide PNIPAM-NP H-bonding sites. Combining NP addition with field application uniquely alters the solution environment and results in fielddependent rheological behavior that is unseen in polymer-only solutions. These investigations provide fundamental understanding on the interplay of magnetic fields and NP addition on PNIPAM thermoresponsivity which can be harnessed for increasingly complex stimuli-responsive materials.

show abstract

Section: Introductionmentioning

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Here, longer NPs led to higher dynamic moduli as the temperature increased above the onset of transition. [ 56 ]…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Effect of nanoparticle loading and magnetic field application on the thermodynamic, optical, and rheological behavior of thermoresponsive polymer solutions

Neal

Kresge

Quan

et al. 2022

Vinyl Additive Technology

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Magnetic field-dependent rheological behavior of thermoresponsive poly(N-isopropylacrylamide) solutions

Neal,

Shetty,

Linn

et al. 2024

Rheol Acta

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Effect of Chain Architecture on the Structure, Dynamics, and Rheology of Thermoresponsive Poloxamer Hydrogels and Associated Blends

White,

Crabtree,

Bates

et al. 2023

Macromolecules

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Poloxamers, ABA triblock polymers composed of a poly(propylene oxide) (PPO) midblock (B) and poly(ethylene oxide) end blocks (A), are widely studied for biomedical applications. Aqueous poloxamer 407 (P407) undergoes a solution-to-gel transition with increasing temperature, driven by the formation and ordering of micelles onto periodic lattices; however, the gel temperature and resulting modulus have limited tunability. Here, reverse P407 (RP407), a BAB polymer of the same composition and molar mass but with an inverted architecture, is synthesized via anionic polymerization. The micellization and gelation temperatures of RP407 are higher than those of P407, and the PPO end blocks allow for intermicelle bridging; however, both single-component solutions favor body-centered cubic (BCC) packings. Furthermore, aqueous RP407 displays a "soft-gel" region with interesting rheological behavior, including viscoelastic aging and thermal hysteresis. Combining P407 and RP407 yields solutions with intermediate transition temperatures and alters the micelle size and packing. While the singlecomponent solutions produce BCC packings, the blends form close-packed structures and larger micelles of higher aggregation numbers. Blends of P407 with an analogous AB diblock (E 111 P 32 ) display similar behavior, whereas RP407/diblock blends form intermediate-sized BCC-packed micelles. These differences in packing and aggregation alter the local environments within the gels, which could have implications for applications such as drug delivery and protein stabilization.

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

Cited by 4 publications

References 115 publications

Effect of nanoparticle loading and magnetic field application on the thermodynamic, optical, and rheological behavior of thermoresponsive polymer solutions

Effect of nanoparticle loading and magnetic field application on the thermodynamic, optical, and rheological behavior of thermoresponsive polymer solutions

Magnetic field-dependent rheological behavior of thermoresponsive poly(N-isopropylacrylamide) solutions

Effect of Chain Architecture on the Structure, Dynamics, and Rheology of Thermoresponsive Poloxamer Hydrogels and Associated Blends

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