Fig. 2

Freeze–fracture electron micrograph of DNA bimodal materials and micrographs taken before and after storage for 6 months. A Freeze–fracture electron micrograph of pure DNNs. The DNNs exhibited a wide distribution range, with no formation of DNFs. B Freeze–fracture electron micrograph of the DNN and DNF mixture. DNNs had a wide range of distribution, and nanoflowers were embedded in the gap of the net. C Freeze–fracture electron micrograph of pure DNFs. DNFs were observed exclusively under the microscope, with the complete absence of DNNs. D DNNs in solid state after lyophilization. The dried DNN powder was present in the form of a crystal. E DNNs dissolved in water after 6 months. The DNN structure remained intact. F DNFs in solid state after lyophilization. The dried DNF powder was present in the form of a crystal. G DNFs dissolved in water after 6 months. The DNF structure remained intact