Study of network composition in interpenetrating polymer networks of poly(N isopropylacrylamide) microgels: The role of poly(acrylic acid)

JOURNAL OF COLLOID AND INTERFACE SCIENCE

卷:545

Article

Nigro, Valentina^1,2  Angelini, Roberta^1,2  Rosi, Benedetta^2,5  Bertoldo, Monica^3,6  Buratti, Elena^1,3  Casciardi, Stefano⁴  Sennato, Simona^1,2  Ruzicka, Barbara^1,2 

[1] ISC CNR, Sede Sapienza, Pzle Aldo Moro 5, I-00185 Rome, Italy

[2] Sapienza Universitet Roma, Dipartimento Fis, Ple Aldo Moro 5, I-00185 Rome, Italy

[3] IPCF CNR, Area Ric, Via G Moruzzi 1, I-56124 Pisa, Italy

[4] Natl Inst Insurance Accid Work INAIL Res, Dept Occupat & Environm Med Epidemiol & Hyg, Via Fontana Candida 1, I-00040 Rome, Italy

[5] Univ Perugia, Dipartimento Fis & Geol, Via A Pascoli, I-06123 Perugia, Italy

[6] ISOF CNR, Via P Gobetti 101, I-40129 Bologna, Italy

关键词: Microgels;    colloidal suspensions;    Dynamic light scattering;    Transmission electron microscopy;    Electrophoretic measurements;   

DOI  :  10.1016/j.jcis.2019.03.004

来源: Elsevier

【 摘 要 】

Hypothesis: The peculiar swelling behaviour of poly(N-isopropylacrylamide) (PNIPAM)(4)-based responsive microgels provides the possibility to tune both softness and volume fraction with temperature, making these systems of great interest for technological applications and theoretical implications. Their intriguing phase diagram can be even more complex if poly(acrylic acid) (PAAc)(5) is interpenetrated within PNIPAM network to form Interpenetrating Polymer Network (IPN)(6) microgels that exhibit an additional pH-sensitivity. The effect of the PAAc/PNIPAM polymeric ratio on both swelling capability and dynamics is still matter of investigation. Experiments: Here we investigate the role of PAAc in the behaviour of IPN microgels across the volume phase transition through dynamic light scattering (DLS),(7) transmission electron microscopy (TEM)(8) and electrophoretic measurements as a function of microgel concentration and pH. Findings: Our results highlight that aggregation is favored at increasing weight concentration, PAAc content and pH and that a crossover PAAc content C-PAAC(9) exists above which the ionic charges on the microgel become relevant. Moreover we show that the softness of IPN microgels can be tuned ad hoc by changing the PAAc/PNIPAM ratio. These findings provide new insights into the possibility to control experimentally aggregation properties, charge and softness of IPN microgels by varying PAAc content. (C) 2019 Elsevier Inc. All rights reserved.

【 授权许可】

Free