Mechanical assembly and magnetic actuation of polydimethylsiloxane-iron composite interconnects for microfluidic systems
Bibliographic record
Abstract
We present magnetically-actuated micromechanical interconnects for microfluidic applications fabricated in-house using PDMS-iron elastomer-ferromagnetic composites (EFCs). Interconnects are fluid-tight, interlocking cylindrical posts and holes whose assembly can be made easier by magnetically actuating the EFC cylinders via axial extension and radial contraction. Towards this goal, we demonstrate magnetic actuation of interconnect structures, and quantify the mechanical disassembly of PDMS-iron interconnects without an applied magnetic field. Previously, we showed the mechanical assembly and disassembly of hybrid combinations of non-magnetic SU-8, silicon, and polydimethylsiloxane (PDMS) microfluidic interconnects. We fabricate EFCs for our interconnects by embedding iron microspheres (<63% by weight) in PDMS. We employed permanent magnets to create 0.045-0.065T constant fields, along with an optics test set-up that included a diode laser and magnification to quantify micron-sized deflections. The interconnects exhibited radial contractions of 3-12% and axial elongation of 2-11%. Without the magnetic field, disassembly forces of 36-71mN were measured by a controlled force linear actuator for PDMS-iron cylinders from PDMS and PDMS-iron holes. This work shows promise for radial contraction of cylinders for assembly with lower forces while maintaining high disassembly forces once the interconnects are assembled and the magnetic field is removed.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".