A Smart Supramolecular Polymer Gel Constructed By Pillar[5]arene

Supramolecular polymers are arrays of repeating units connected via non-covalent bond interactions.Because non-covalent interactions are reversible,supramolecular polymers have a stimulus response.Supramolecular polymer can fix solvents to form supramolecular gels.After the gel is formed,the stimulus-responsiveness endows the supramolecular polymer degradable,self-healing and expansion-contraction and other properties.It can prepare self-degrading,self-healing,3D-printable and other functional materials.So it is called intelligent soft material.Pillar[5]arene,a new macrocyclic host material with high symmetry,stability and good modification performance,are good structural units for constructing intelligent supramolecular polymer materials.Firstly,this paper summarizes the research on supramolecular polymers and pillar[5]arene-based supramolecular polymer gels.At present,supramolecular polymers constructed by pillar[5]arene are mainly linear or branched,and there are relatively few supramolecular polymers with side chains.The mechanical strength of the constructed supramolecular polymer gel is generally weak.Their functions are mainly manifested in various stimuli-responsiveness.Secondly,a polymer chain pendant with pillar[5]arene hydrocarbons is synthesized by radical polymerization.A guest molecule containing azo groups is also synthesized.Each compound molecule has been characterized in detail.The bonding constant of pillar[5]arene and guest molecules in 1H NMR nuclear magnetic titration can reach(4.5 ± 0.2)× 104 M-1.Finally,the pillar[5]arene in the polymer chain and the guest molecule formed complexes and then a gel come into being.The gel was characterized by scanning electron microscopy experiments,rheological experiments,and mechanical experiments.The gel has high mechanical properties,can be shaped,and has self-healing properties,showing a sensitive response to temperature,light,etc.This is the firstly reported pillar[5]arene-based supramolecular polymer gel system with strong mechanical properties that can be shaped.This research provides new prospects for the application of supramolecular polymer gels in the field of smart materials.