Autopore 9520

All Raman spectra, including the SERS analysis, were analyzed using Raman spectroscopy (HORIBA, Osaka, Japan, LabRAM HR-800). The laser power was 3 mW, the excitation wavelength was 532 nm, and a × 50 objective with NA = 0.5 was used. The morphological characteristics were analyzed by using a field-emission scanning electron microscopy (FE-SEM, HITACHI, Tokyo, Japan, S-4800) at 15 kV. Surface activation energy analyses were performed by using a water contact angle (WCA) analyzer (SEO, Phoenix MT, Seoul, Republic of Korea). Characterization of the pore distribution of the samples was performed using mercury intrusion porosimetry (Micromeritics, Norcross, GA, USA, AutoPore 9520).

All Raman spectra, including the SERS analysis, were analyzed using Raman spectroscopy (HORIBA, Osaka, Japan, LabRAM HR-800). The laser power was 3 mW, the excitation wavelength was 532 nm, and a × 50 objective with NA = 0.5 was used. The morphological characteristics were analyzed by using a field-emission scanning electron microscopy (FE-SEM, HITACHI, Tokyo, Japan, S-4800) at 15 kV. Surface activation energy analyses were performed by using a water contact angle (WCA) analyzer (SEO, Phoenix MT, Seoul, Republic of Korea). Characterization of the pore distribution of the samples was performed using mercury intrusion porosimetry (Micromeritics, Norcross, GA, USA, AutoPore 9520).

The pore structure was determined by mercury intrusion porosimetry (AutoPore 9520, Micromeritics, Norcross, GA, USA), in which the specimen was prepared by stopping the hydration reactions using acetone and an aspirator. A pressure ranging from 3.64 × 10³ to 4.14 × 10⁸ Pa was applied to the pores, corresponding to a maximum and minimum pore size of 340 μm and 3 nm, respectively. The mechanical strength was evaluated by measuring the compressive strength of the cubic specimens at a pressing speed of 4 mm/min. Impedance spectra were acquired using an impedance analyzer (SI 1260, Solartron, UK) with an oscillating voltage of 0.1 V between 10 MHz and 1 Hz. A stainless steel plate was employed as an electrode, and the distance between electrodes was 40 mm. A three-point bending test was used on the 3D-printed, beam-shaped specimens to evaluate mechanical tensile properties using a custom-made universal test machine at a pressing speed of 0.1 mm/min.