Assembling PNIPAM-Capped Gold Nanoparticles in Aqueous Solutions

Journal Article · Wed Nov 22 04:00:00 EST 2023 · ACS Macro Letters

DOI:https://doi.org/10.1021/acsmacrolett.3c00617· OSTI ID:2572960

Nayak, Binay P; Kim, Hyeong Jin; Nayak, Srikanth; Wang, Wenjie; Bu, Wei; Mallapragada, Surya K.; Vaknin, David

Employing small-angle X-ray scattering (SAXS), we explore the conditions under which assembly of gold nanoparticles (AuNPs) grafted with the thermosensitive polymer poly(N-isopropylacrylamide) (PNIPAM) emerges. We find that short-range order assembly emerges by combining the addition of electrolytes or polyelectrolytes with raising the temperature of the suspensions above the lower-critical solution temperature (LCST) of PNIPAM. Our results show that the longer the PNIPAM chain is, the better organization in the assembled clusters. Interestingly, without added electrolytes, there is no evidence of AuNPs assembly as a function of temperature, although untethered PNIPAM is known to undergo a coil-to-globule transition above its LCST. This study demonstrates another approach to assembling potential thermosensitive nanostructures for devices by leveraging the unique properties of PNIPAM.

• Research Organization: Argonne National Laboratory (ANL)
• Sponsoring Organization: US Department of Energy; National Science Foundation (NSF); USDOE Office of Science - Office of Basic Energy Sciences; USDOE Office of Science - Office of Basic Energy Sciences - Materials Sciences and Engineering Division
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 2572960
• Journal Information: ACS Macro Letters, Journal Name: ACS Macro Letters Journal Issue: 12 Vol. 12
• Country of Publication: United States
• Language: English