On‐Surface Non‐Equilibrium Phase Evolution Toward 2D Supramolecular Glass

ABSTRACT

Controlling crystalline‐to‐glassy transitions represents a vibrant frontier in supramolecular chemistry and condensed matter physics, providing fundamental insights into non‐equilibrium dynamics and enabling functional tunability for elasticity electronics and phase‐change devices. Conventional two‐dimensional (2D) supramolecular assembly follows an enthalpy‐dominated thermodynamic paradigm, restricting the exploration of non‐equilibrium supramolecular glasses (SMGs). Herein, we report the controlled construction of a non‐equilibrium SMG on Ag(111) using in situ‐generated triradical triphenyl‐triazine molecules. The electrophilic triazine core enriches charge density at radical sites and strengthens molecule–substrate interfacial coupling, imposing pronounced kinetic constraints at the surface. Upon thermal activation, the system follows a non‐monotonic, four‐phase evolution that involves a thermodynamically uphill transformation. Rather than directly relaxing to the global thermodynamic minimum, it is kinetically arrested into a metastable glassy state with short‐range order and long‐range disorder. This work revises the conventional enthalpy‐dominated view of supramolecular assembly and establishes a backbone‐modulated radical kinetic strategy for rational fabrication of disorder‐tunable 2D supramolecular materials.