The study of polymer materials with stimulation responsibility has been one of the current cores in polymer research. Serving as an innovative stimulating source, mechanical force owns several properties different from traditional sources such as light and heat. Mechanical forces can be divided into two categories from their origins, i.e. the microscopic mechanical force and the macroscopic one. Mechanical force at macroscopic level has long been utilized to process and mold polymer materials even since ancient time of human history. However, the principles and applications of microscopic mechanical force responsive polymer has not been focused on until the past decades. In this review, we start from the analysis of the mechanochemical principles, followed by the exhibition of various mechanical force responsive systems divided into different groups. Specially, according to the bonds responsively broken by mechanical force, we divided them into covalent bond system and non-covalent bond system. The covalent bond systems can be further separated into cyclic structure systems and linear ones. Additionally, this article has provided a window into the existing interdisciplinary applications, including mechanical force stimulated racemic isolation, mechanical force stimulated catalyst activation, mechanical force assisted mechanism study, and so on. We hope the review can have the potential to offer some meaningful points to the en route development of mechanochemical systems and their further applications.

Contents
1 Introduction
2 General principles of mechanical force responsive polymer systems
3 Catalogs of mechanical force responsive polymer systems in polymer chemistry
3.1 Covalent bond systems
3.2 Non-covalent bond systems
4 Applications
4.1 Mechanical force stimulated racemic isolation
4.2 Mechanical force stimulated catalyst activation
4.3 Active species generation from mechanical force stimulation
4.4 Mechanical force assisted mechanism study
5 Conclusion and outlook