Femtosecond laser patterned superhydrophobic/superhydrophilic substrates with sequential microdroplet evaporation:...

Superhydrophobic surface-enhanced Raman scattering (SERS) substrates allow ultrasensitive molecular detection through microliter-scale droplets. However, their widespread application is hindered by prolonged evaporation processes exceeding one hour. This study develops a sequential microdroplet evaporation strategy using femtosecond laser patterned superhydrophobic/superhydrophilic (SH/SHL) substrates. By sequentially evaporating 1 μL analyte units with sequential heating, solute dispersion caused by sustained thermal exposure can be successfully mitigated. Experimental data reveal this method reduces evaporation time for 8 μL R6G from 82 minutes to 4.3 minutes, while retaining the 10^-14 M detection limit through precise deposition control. The SERS substrate demonstrates an enhancement factor of 8.81 × 10¹⁰, achieving 19-fold efficiency enhancement over conventional approaches. This innovation effectively resolves the efficiency-sensitivity paradox in SH SERS-based detection systems.