Translational and rotational diffusion coefficients of gold nanorods functionalized with a high molecular weight, thermoresponsive ligand: a depolarized dynamic light scattering study. Issue 15 (10th March 2021)

• Record Type: Journal Article
• Authors: Feller, Déborah; Otten, Marius; Hildebrandt, Marco; Krüsmann, Marcel; Bryant, Gary; Karg, Matthias
• Is Part Of: Soft matter. Volume 17:Issue 15(2021)
• Page Start: 4019
• Page End: 4026
• Publication Date: 2021-03-10
• Subjects: Soft condensed matter -- Periodicals; 530.413
• DOI: 10.1039/d1sm00077b
• Languages: English
• ISSNs: 1744-683X

Abstract

Abstract : Collapse of high molecular weight, thermoresponsive polymer ligands on gold nanorods increases the translational and rotational diffusion coefficients due to an increase in aspect ratio and thus particles become less ellipsoidal. Abstract : Probing the rotational and translational diffusion and colloidal stability of nanorods is of significant fundamental interest with implications for many different applications. Recently R. Nixon-Luke and G. Bryant presented a method to analyze angle-dependent depolarized dynamic light scattering data allowing for the clear separation of the translational and rotational diffusion coefficients of gold nanorods in dilute suspension (R. Nixon-Luke and G. Bryant, Part. Part. Syst. Charact., 2018, 36, 1800388). In the present work we applied this analysis to gold nanorods decorated with high molecular weight, thermoresponsive poly- N -isopropylacrylamide ligands, which results in particles with lower effective aspect ratios. The temperature response of the ligand shell is studied. We precisely determine the translational and rotational diffusion coefficients over a broad range of temperatures and the results are compared to theoretical predictions. The results show that as temperature increases the ligands collapse, and the effective aspect ratio increases as the particle shape transitions from prolate spheroid at low temperatures to more cylindrical at high temperatures.