Lahir di Kudus, 26 Maret 1979. Perempuan yang memiliki NIP 197903262005012001 adalah staf Pengajar pada Fakultas Matematika dan Ilmu Pengetahuan Alam UNS. Riwayat pendidikan tinggi yang berhasil ditempuh adalah tahun 2003 lulus sarjana (S-1) dari Universitas Sebelas Maret pada bidang ilmu: Kimia, tahun 2009 berhasil menyelesaikan master (S-2) dari Nagoya University pada bidang ilmu: Chemistry, dan pada tahun 2012 telah berhasil menyelesaikan program Doktor (S-3) dari Shizuoka University untuk bidang ilmu: Nanovision Technology and Engineering. Judul dan ringkasan disertasi sebagai berikut.
SURFACE MODIFICATION OF GRAPHITE-ENCAPSULATED IRON COMPOUND MAGNETIC NANOPARTICLES BY RADIO FREQUENCY INDUCTIVELY-COUPLED PLASMA
In general, the objective of this work is to prepare the potential candidate magnetic nanomaterial for bioapplication with high biocompatibility. We proposed the graphite-encapsulated iron compound magnetic nanoparticles as a candidate of nanomaterial due to their potential properties on physical, chemical and biological fields. In detail, this study was performed in three steps, starting from the nanoparticle fabrication, nanoparticle surface modification by plasma treatment, optimization of the process of ammonia plasma treatment with modified technique especially for powder sample and leading to biomolecules immobilization for testing the treated nanoparticle capabilities. In the first stage, the iron encapsulated inside graphite layer is successfully synthesized by arc discharge method using helium and methane gas with ratio 4:1 kept in gas pressure of 100 torr. The fabricated nanoparticle was confirmed and characterized well using SEM, XRD, EDS and TEM that showed the iron core is coated by graphite layers. In the second stage, the synthesized nanoparticles, graphite encapsulated iron compound magnetic nanoparticles, was treated in plasma processing generated by inductively-coupled radio frequency plasma device. After the plasma treatment, the surface of the outmost graphene layer is successfully covered by nitrogen-containing groups definitively assigned by XPS spectra and the STEM-EDS elemental mapping. The nitrogen-containing groups formed during the post-treatment plasma selectively attached on the outmost of graphene layer. The inner structure of inner graphene layer and the iron core are still found in stable condition indicates that the applied plasma condition allows the efficient covalent functionalization of nitrogen-containing group to the surface particles without give any destruction. The result shows the highest values of N/C atomic ratio of 5.4 % is obtained by applying 10 min of Ar plasma pre-treatment and 2 min of NH3 plasma post-treatment conducted in RF power of 80W and gas pressure of 50 Pa. As the modified setup, pulsed particle explosion technique, was successfully built by applying high negative voltage to the metal substrate as sample stage inside the chamber during plasma processing generated by inductively-coupled radio frequency plasma device. Applying the initial biasing only in a few seconds with condition of voltage -1 kV, frequency 1 kHz and 50 % duty ratio in ammonia plasma provided much significant results of the increasing N1s peak intensity in the XPS spectra. The other result analyzed by TEM shosw that no significant damages found on the nanoparticle structures indicates that the present technique is suitable for surface modification for powder sample due to its high efficient of surface modification without gave any structural destruction. Finally, in the biomolecules section, the primary amino groups grafted after Ar plasma pre-treatment followed by NH3 plasma post-treatment appeared to play an important role in dextran immobilization. The dispersion property of nanoparticles in dextran dissolved in water was significantly improved by surface plasma treatment. The primary amines provide a high selective reaction between aldehyde group of oxidized dextran and amino groups of treated nanoparticles, hence the covalent immobilization was successfully achieved. The dextran immobilization was confirmed by XPS and HR-TEM analysis followed by amino group derivatization. The deconvoluted peak at ~398.6 eV (C=N) as an evidence for Schiff-base linkages between dextran and amino groups on the treated nanoparticles, increased with the increasing of the dextran concentration. This result is consistent with the decrease of free amino group percentage remaining on the nanoparticles surfaces which was evidenced when the dextran concentration increased. High magnification images obtained by HR-TEM allowed the visual observations of the differences between surface morphology of nanoparticles before and after dextran immobilization.
