Chemistry Reference
In-Depth Information
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CHAPTER 3
Molecular Gels Responsive to
Physical and Chemical Stimuli
MING XIONG,
a
CHENG WANG,*
a
GUANXIN ZHANG
b
AND DEQING ZHANG*
b
a
College of Chemistry and Molecular Sciences, Wuhan University, Wuhan
430072, China;
b
Beijing National Laboratory for Molecular Sciences,
Organic Solids Laboratory, Institute of Chemistry, Chinese Academy of
Sciences, Beijing 100190, China
*Email: dqzhang@iccas.ac.cn; chengwang@whu.edu.cn
3
.
3.1 Introduction
Apart from studies on the rational design of LMWGs, extensive efforts have
been made to prepare stimuli-responsive molecular gels.
1-3
The gel-solution
transition is thermally reversible for molecular gels. Besides heating and cooling
the gel-solution transition can also be induced by other physical and chemical
stimuli for gels with appropriate LMWGs. The physicochemical properties are
varied accompanying the gel-solution transition (Figure 3.1). These stimuli-
responsive molecular gels are promising soft materials for a diverse range of
applications.
In principle, external stimuli can be classified (Figure 3.1) as physical and
chemical ones. Heat, mechanical forces, ultrasound waves, and UV-vis light
can be included as physical stimuli, whereas acid-base reagents, salts with
appropriate anions and cations, neutral molecules, redox reagents and enzymes
can be used as chemical stimuli. In this chapter, we will highlight recent pro-
gress on molecular gels responsive to physical and chemical stimuli. First, the
