Solvothermal vapor annealing and environmental control setup with adjustable magnetic field module for GISAXS studies

TL;DR

The work addresses the need for precise environmental control in GISAXS studies of thin-film self-assembly by developing a compact, modular STVA chamber with an adjustable magnetic-field module. The platform integrates solvent-vapor humidity control, temperature regulation, and an in situ spectral reflectometry system, and is compatible with lab-based GISAXS and synchrotron setups such as RUCSAXS/XEUSS. Key contributions include a drawer-based modular design for rapid sample exchange, a calibrated solvent-concentration monitoring unit, and validated fast fill/quench performance alongside magnetic-field mapping validated by Gauss measurements and FEM simulations. Four research demonstrations—magnetic-field–driven nanoparticle assembly, ex situ GISAXS of di‑BCP, in situ GISAXS during STVA, and brush-layer–assisted ordering—underscore the setup’s versatility for advancing high‑quality, field-responsive thin-film architectures with potential extension to GISANS and related scattering modalities.

Abstract

A compact, modular environmental control and solvothermal vapor annealing chamber designed for maintaining a controlled atmosphere with regard to solvent humidity and temperature is presented. The setup allows ex situ and in situ grazing incidence small-angle X-ray scattering (GISAXS) investigations of thin film self-assembly and reorganization. Its modular slotting system enables stable reconfiguration, including the integration of an adjustable magnetic field module. The temperature is maintained via a water-based heating and cooling loop supplemented by resistive elements, and the solvent vapor environment is regulated using a commercial controlled mixing and evaporation unit. The performance of the setup is validated through measurements of fill and quench times together with magnetic field mapping with Gauss meter measurements and finite element simulations. Further, the versatility of the setup is demonstrated with four research examples using the chamber for solvothermal vapor annealing of block copolymer thin films together with lab-based ex situ and in situ GISAXS measurements. The portable new design offers robust environmental control and flexibility for advanced thin film investigations both in the lab and at large scale facilities. The design can be adapted for grazing incidence small-angle neutron scattering, GISANS.

Figures (12)

• Figure 1: (a) Base drawer with large sample stage, (b) Magnetic drawer featuring a smaller sample stage designed for integrating permanent magnets, seen installed here on either side of the sample stage, to produce adjustable in‐plane and out‐of‐plane fields, c) Underside of base drawer featuring a mixing cavity for the incoming vapor and d) Chamber housing covered in insulation sheets and displaying the side with the opening where drawers are slotted in. An X-ray transparent window made of Kapton is also seen on the figure.
• Figure 2: Photographs of the STVA chamber mounted inside the RUCSAXS sample‑environment enclosure. (a) Overview with key components labeled: (1) X‑ray beam from source, (2) Kapton windows in the beam path, (3) fiber-optic probe, (4) SVC unit, and (5) linear and rotary motion stage. (b) Sample mounted on the magnetic drawer stage, with axes annotated: the x and y directions lie in the sample plane, with x along the beam direction, while z is normal to the sample surface (out of plane).
• Figure 3: (a) The absorbance as function of time during chamber filling with fits to eq. \ref{['A1']} for both magnetic and base drawer. (b) The absorbance as function of time and fits to eq. \ref{['A2']} during quenching.
• Figure 4: Magnetic field magnitude in mT measured with a Gauss probe (solid lines) and computed by FEM (dashed lines) at a height of $z=9$ mm above the sample stage, plotted versus the number of magnets (n) inserted on each side of the stage. Center values correspond to $(x,y)=(0,0)$ and edge values to $(x,y)=(\pm11~\mathrm{mm},0)$. Circle markers denote center data and square markers edge data.
• Figure 5: Evaporation rates of BCP/nanoparticle solution droplets left to dry in the STVA chamber with 80% or nominally 100% toluene-saturated nitrogen flow, as recorded from the halfway point of an X-ray scan along the droplet normal. Also shown are linear fits (dashed lines) to the data (filled dots or squares)