Segregation of mass at the periphery of N -isopropylacrylamide-co-acrylic-acid microgels at high temperatures

John S. Hyatt, Changwoo Do, Xiaobo Hu, Hong Sung Choi, Jin Woong Kim, L. Andrew Lyon, Alberto Fernandez-Nieves

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

We investigate poly(N-isopropylacrylamide) (pNIPAM) microgels randomly copolymerized with large mol % of protonated acrylic acid (AAc), finding that above the lower critical solution temperature the presence of the acid strongly disrupts pNIPAM's collapse, leading to unexpected new behavior at high temperatures. Specifically, we see a dramatic increase in the ratio between the radius of gyration and the hydrodynamic radius above the theoretical value for homogeneous spheres, and a corresponding increase of the network length scale, which we attribute to the presence of a heterogeneous polymer distribution that forms due to frustration of pNIPAM's coil-to-globule transition by the AAc. We analyze this phenomenon using a Debye-Bueche-like scattering contribution as opposed to the Lorentzian term often used, interpreting the results in terms of mass segregation at the particle periphery.

Original languageEnglish
Article number030302
JournalPhysical Review E - Statistical, Nonlinear, and Soft Matter Physics
Volume92
Issue number3
DOIs
StatePublished - Sep 29 2015

Fingerprint

Dive into the research topics of 'Segregation of mass at the periphery of N -isopropylacrylamide-co-acrylic-acid microgels at high temperatures'. Together they form a unique fingerprint.

Cite this