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Bioinspired Simultaneous Changes in Fluorescence Color, Brightness and Shape of Hydrogels Enabled by AIEgens

submitted on 18.09.2019 and posted on 23.09.2019 by Zhao Li, Xiaofan Ji, Junyi Gong, Yubing Hu, Wenjie Wu, Xinnan Wang, Hui-Qing Peng, Ryan Tsz Kin Kwok, Jacky W. Y. Lam, Ben Zhong Tang
Development of stimuli-responsive materials with complex practical functions is significant for achieving bioinspired artificial intelligence. It is challenging to fabricate stimuli-responsive hydrogels showing simultaneous changes in fluorescence color, brightness and shape in response to one stimulus. Herein a bilayer hydrogel strategy was designed by utilizing an aggregation-induced emission luminogen (AIEgen) tetra-(4-pyridylphenyl)ethylene (TPE-4Py) to fabricate hydrogels with the above capabilities. Bilayer hydrogel actuators with ionomer of poly(acrylamide-r-sodium 4-styrenesulfonate) (PAS) as matrix of both active and passive layers and TPE-4Py as the core function element in the active layer were prepared. At acidic pH, the protonation of TPE-4Py led to fluorescence color and brightness changes of the actuators and the electrostatic interactions between the protonated TPE-4Py and benzenesulfonate groups of PAS chains in the active layer caused the actuators to deform. The proposed TPE-4Py/PAS-based bilayer hydrogel actuators with such responsiveness to stimulus provide pregnant insights in the design of intelligent systems and are highly attractive material candidates in fields of 3D/4D printing, soft robots and smart wearable devices.


the National Science Foundation of China(21788102, 21490570 and 21490574)

the Research Grant Council of Hong Kong (16308116, 16305618 and C6009-17G)

the Science and Technology Plan of Shenzhen (JCYJ20160229205601482, JCY20170307173739739 and JCYJ20170818113602462)

the Innovation and Technology Commission (ITC-CNERC149C01)


Email Address of Submitting Author


The Hong Kong University of Science and Technology



ORCID For Submitting Author


Declaration of Conflict of Interest

The authors declare no competing financial interest.