Reversible stability of colloids switched by CO2 based on polyhexamethylene guanidine

Xiaoling Huang; Zhuoyan Zhu; Zheng Luo; Weihang Zhao; Yufeng Wang; Yiwen Shi; Xin Su

doi:10.1039/d2sm00811d

Reversible stability of colloids switched by CO₂ based on polyhexamethylene guanidine

Soft Matter. 2022 Oct 26;18(41):8046-8052. doi: 10.1039/d2sm00811d.

Authors

Xiaoling Huang¹, Zhuoyan Zhu², Zheng Luo¹, Weihang Zhao¹, Yufeng Wang¹, Yiwen Shi¹, Xin Su¹

Affiliations

¹ Polymer Research Institute, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, 610065, China. xinsu@scu.edu.cn.
² Research Institute of Petroleum Exploration and Development, PetroChina, Beijing, 100083, China.

PMID: 36227104
DOI: 10.1039/d2sm00811d

Abstract

The stability of a colloid, including emulsion and polymer latex, can be destroyed irreversibly by the addition of salt. Using the CO₂ stimulus, amines can be converted into organic ammonium salts reversibly, which can access the switching of colloids. Polyhexamethylene guanidine (PHMG), was chosen as a switchable amine. The conductivity of PHMG aqueous solution switched by adding and removing CO₂. Surface tension measurements verified that, under CO₂, the critical micelle concentration of sodium dodecyl benzene sulfonate (SDBS) decreased from 1.0 × 10^-3 to 5.0 × 10^-4 M with the addition of PHMG. The crude oil emulsion containing SDBS and PHMG was destroyed and restored reversibly by the treatment with CO₂ and N₂. The polystyrene latex also occurred an obvious stratification after sparging with CO₂ and returned a homogeneous phase upon bubbling N₂. This study is intended to pave the way for colloids which has reversible stability in response to CO₂ stimulation.