Two-Way CO2-Responsive Polymer Particles with Controllable Amphiphilic Properties

Yeong-Tarng Shieh; Yao-Chuan Yeh; Chih-Chia Cheng

doi:10.1021/acsomega.9b03319

Two-Way CO₂-Responsive Polymer Particles with Controllable Amphiphilic Properties

ACS Omega. 2020 Jan 22;5(4):1862-1869. doi: 10.1021/acsomega.9b03319. eCollection 2020 Feb 4.

Authors

Yeong-Tarng Shieh¹, Yao-Chuan Yeh¹, Chih-Chia Cheng²

Affiliations

¹ Department of Chemical and Materials Engineering, National University of Kaohsiung, 700 Kaohsiung University Road, Nanzih District, Kaohsiung 81148, Taiwan.
² Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, 43, Keelung Road, Section 4, Da'an District, Taipei 10607, Taiwan.

Abstract

Multiple stimuli-responsive amphiphilic block copolymers of poly(methacrylic acid) (PMAA) and poly(2-dimethylaminoethyl methacrylate) (PDMAEMA) were used as emulsifiers to prepare two-way CO₂ stimuli-responsive poly(methyl methacrylate) (PMMA) latex particles via aqueous emulsion polymerization. The polymerization at pH 2 and 50 °C produced mainly PDMAEMA-surfaced PMMA latex particles, whereas the polymerization at pH 12 and 50 °C produced mainly PMAA-surfaced particles. Both types of latex particles appeared to precipitate at higher pH values from the emulsifier of a longer PDMAEMA block length. The direction from precipitation to dispersion for PDMAEMA-surfaced particles or from dispersion to precipitation for PMAA-surfaced particles in response to CO₂ bubbling of the pH 12 dispersion of particles depended on the PDMAEMA block length. Together, this study reveals that-by tuning the PDMAEMA block length in PMAA-b-PDMAEMA used as an emulsifier and polymerization at pH 2 or 12-PMMA latex particles can exhibit two-way CO₂ responsiveness between dispersion and precipitation. Thus, due to their simple preparation and unique dual pH and CO₂ responsiveness, these newly developed PMAA-b-PDMAEMA emulsifiers provide a highly efficient approach for the development of smart PMMA latex nanoparticles with desirable multifunctional properties.