Characterization of Single-Chain Nanoparticles and Star Polymers using Gel Permeation Chromatography combined with Viscometric Studies

Ashley Hanlon, and Erik Berda*. Department of Chemistry, University of New Hampshire.

Star Polymer Design

Star Polymer Synthesis

MHS and Conformation Plots

Summary and Conclusions

Acknowledgements

Introduction

Single-Chain Nanoparticles

References(1) Frank, P. G.; Tuten, B. T.; Prasher, A.; Chao, D.; Berda, E. B. Macromolecular rapid communications 2014, 35, 249-253. (2) Gao, Haifeng, Macromol. Rapid Commun. 2012, 33, 722-734. (3) Gao H.; Matyjaszewski, K..J. Am. Chem. Soc., 2007, 129, 11828-11834.(4) Schneider, Y.; McVerry, B.; Bazan, G. Macromol. Chem. Phys. 2011, 212, 507-514. (5) Lyon, C. K.; Prasher, A.; Hanlon, A. M.; Tuten, B. T.; Tooley, C. A.; Frank, P. G.; Berda, E. B. Polym. Chem. 2015, 6, 181-197.

Scheme 1: Schematic representation of star polymer design

This research serves to explore the underutilized abilities of a GPC combined with multiple in-line detectors. Much information can be gained by exploiting the viscometric and multi-angle light scattering data to distinguish between different polymer architectures. Exploiting the abilities of GPC characterization of star polymers and SCNPs will help to identify their unique properties and potentially aid to expand the value of utilizing GPC for other types of macromolecular architectures.

The exploration of different polymer architectures, such as star polymers or single-chain nanoparticles, is rapidly increasing due to the ability to synthetically tailor specific properties and the potential to utilize these types of polymers in many areas including catalysis, imaging, nanoreactors, and nanomedicine. While both of these polymer systems show promising properties and applications their characterization can be a challenge. Gel permeation chromatography (GPC) is a vital tool in polymer characterization and when using multiple in-line detectors such as multi-angle light scattering (MALS) and viscometry much qualitative and quantitative data can be gained. We have been able to demonstrate the successful synthesis, and isolation of multiple arm star polymers and single-chain nanoparticles. A detailed characterization was achieved through the use of GPC to aid in the analysis of unique macromolecular architectures. A contrast of viscometric data of unique polymer architectures and linear polymer analogs supported the transformation from rod like arms or linear polymer chains to a sphere like highly branched stars or nanoparticles.

A contrast of viscometric data of star polymers to linear polymer analogs through the use of molecular conformation plots indicate the star polymers are highly branched species. The viscosity properties of the star polymers differ significantly from linear polymers. Comparisons of the slopes from Mark-Houwink plots of log intrinsic viscosity as a function of log molecular weight supported the transformation from rod like arms to a sphere like star.

The Army Research Office for support through award W911NF-14-1-0177, and NIST for support through award 70NANB15H060

Polymer SCNP

Peak Mn

(kg/mol)

Mw

(kg/mol)

PDI R(nm) Intrinsic viscosity

(mL/g)

Arm 26.5 35.4 1.23 3.7 1.3

Purified Star

747 1016 1.36 11.0 12.2

Peak Mn

(kg/mol)

Mw

(kg/mol)

PDI R(nm) Intrinsic viscosity

(mL/g)

Arm 15.3 17.8 1.17 3.1 11.8

Purified Star

340 380 1.12 11.1 12.6

Mn (kg/mol) Mw (kg/mol) PDI R(nm) Intrinsic viscosity

(mL/g)

MI 5.08 5.55 1.09 2.4 14.8

Copolymer 81.0 104 1.28 6.4 21.5

Peak Mn (kg/mol) Mw (kg/mol) PDI R(nm) Intrinsic viscosity

(mL/g)PMMA Arm 11.5 11.8 1.03 2.3 5.8

PS Arm 2.56 2.70 1.05 1.3 4.6

Star 248 283 1.14 7.2 10.0

Peak Mn (kg/mol) Mw (kg/mol) PDI R(nm) Intrinsic viscosity

(mL/g)

Star 1020 1330 1.33 9.9 8.6

Polystyrene standard

925 950 1.03 27.1 152.8

Mn (kg/mol) Mw (kg/mol) PDI R(nm) Intrinsic viscosity

(mL/g)

Polymer 26.3 30.7 1.17 2.8 5.0

Nanoparticle 50.3 62.3 1.24 2.4 0.5

Star Polymer VS. Linear Polymer

Mark-Houwink-Sakurada Plot

AH.1.60.pure[AH(2-11-14)]AH 1.13 p[BT (ONA Ashley Rongfang) (6-11-13)]

Molar Mass (g/mol)

41.0x10

51.0x10

Intr

insi

c V

isco

sity

(m

L/g)

10.0

Mark-Houw ink-Sakurada properties

K = (6.519 ± 0.182) e-1 mL/g, a = (3.172 ± 0.025) e-1K = (1.387 ± 0.187) e-3 mL/g, a = (9.165 ± 0.146) e-1

Rh(v) conformation plot

AH 1.13 p[BT (ONA Ashley Rongfang) (6-11-13)]AH.1.60.pure[AH(2-11-14)]

Molar Mass (g/mol)

41.0x10

51.0x10

Hyd

rodyn

amic

Rad

ius

(v)

(nm

) 10.0

conformation plot slope

0.60±0.010.44±0.01

Arm Arm

Star Star

Peak Mn

(kg/mol)

Mw

(kg/mol)

PDI R(nm) Intrinsic viscosity

(mL/g)

Arm 2.56 2.70 1.05 1.3 4.6

Star 1020 1330 1.33 9.9 8.6

Purification of Star Polymers