Digital polymers with precisely ordered units acting as the coded 0- or 1-bit, are introduced as a promising option for molecular data storage. However, the pursuit of better performance in terms of high storage capacity and useful functions never stops. Herein, we propose a concept of an information-coded 2D digital dendrimer. The divergent growth via thiol-maleimide Michael coupling allows precise arrangements of the 0- and 1-bits in the uniform dendrimers. A protocol for calculating the storage capacity of non-linear binary digital dendrimer is established based on data matrix barcode, generated by the tandem mass spectrometry decoding and encryption. Furthermore, the generated data matrix barcode can be read by a common hand-held device to cater the applications such as item identification, traceability and anticouterfeiting purpose. This work demonstrates the high data storage capacity of a uniform dendrimer and uncovers good opportunities for the digital polymers.

Digital polymers as promising molecule-level storage media have aroused more and more interest. The application of digital polymers strongly relies on efficient message writing and reading. Herein, we report the rational design of a digital polymer based on thiol–maleimide Michael coupling. Bromine was used as the precursor of the thiol group via thiourea/bromine nucleophilic substitution. This chemistry enabled efficient writing with excellent group tolerance and structural diversity. Importantly, the terminal bromine acting as an isotope tag enabled efficient reading by tandem mass spectrometry (MS/MS) sequencing. Moreover, to produce a more predictable tandem MS-induced fragmentation pattern, a computer simulation of the bond dissociation energy (BDE) was used. It was found that when the sulfur was oxidized to sulfoxide, the carbon–sulfur bond adjacent to the succinimide group had a much lower BDE, ∼32.2 kcal mol⁻¹, allowing selective chain cleavage during MS/MS sequencing. The MS/MS sequencing of the sulfoxide–succinimide-linked digital polymer enabled efficient reading by creating an easily readable and predictable MS fragmentation pattern. The engineered digital polymers were endowed with both efficient writing and reading, which advanced the research and application of digital polymers.

Cyclic polymers have attracted more and more attentions in recent years because of their unique topological structures and characteristic properties in both solution and bulk state. There are relatively few reports on cyclic polymers, partly because of the more demanding synthetic procedures. In recent years, “click” reaction, especially Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC), has been widely utilized in the synthesis of cyclic polymer materials because of its high efficiency and low susceptibility to side reactions. In this review, we will focus on three aspects: (1) Constructions of monocyclic polymer using CuAAC “click” chemistry; (2) Formation of complex cyclic polymer topologies through CuAAC reactions; (3) Using CuAAC “click” reaction in the precise synthesis of molecularly defined macrocycles. We believe that the CuAAC click reaction is playing an important role in the design and synthesis of functional cyclic polymers.