TY - JOUR
T1 - Segregation of mass at the periphery of N -isopropylacrylamide-co-acrylic-acid microgels at high temperatures
AU - Hyatt, John S.
AU - Do, Changwoo
AU - Hu, Xiaobo
AU - Choi, Hong Sung
AU - Kim, Jin Woong
AU - Lyon, L. Andrew
AU - Fernandez-Nieves, Alberto
N1 - Publisher Copyright:
© 2015 American Physical Society. ©2015 American Physical Society.
PY - 2015/9/29
Y1 - 2015/9/29
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=84943339466&partnerID=8YFLogxK
U2 - 10.1103/PhysRevE.92.030302
DO - 10.1103/PhysRevE.92.030302
M3 - Article
C2 - 26465408
AN - SCOPUS:84943339466
SN - 1539-3755
VL - 92
JO - Physical Review E - Statistical, Nonlinear, and Soft Matter Physics
JF - Physical Review E - Statistical, Nonlinear, and Soft Matter Physics
IS - 3
M1 - 030302
ER -