# NanoArc Chemistry Applications Idea Register **Status:** Concept backlog; not experimentally validated **Recorded:** 2026-08-13 **Authority:** Tristan selects priorities and authorizes experimental work This register preserves candidate chemistry and materials applications for NanoArc and future ACE work. Usefulness ratings are planning judgments, not evidence of feasibility, safety, compatibility, or performance. Each candidate requires its own literature review, hazards review, materials-compatibility check, experiment plan, and acceptance criteria before implementation. | Candidate | NanoArc usefulness | Future ACE usefulness | Why it is interesting | |---|---:|---:|---| | Sodium acetate trihydrate | High | High | Phase-change thermal storage; directly relevant to thermal cartridges and temperature-control experiments. | | Sodium citrate / citrate salts | Medium-High | High | Metal-ion complexing and buffering; potentially useful for exploring electroplating without immediately moving to exotic plating chemistry. | | Calcium alginate hydrogel | Potentially high | High | Immobilizes liquids and electrolytes; may provide a controllable wet interface for the plating-pen concept. | | Agar or gel-electrolyte formulations | Medium-High | High | Another route to retaining an electrolyte at a tool tip without a conventional reservoir or bath. | | Graphite/binder conductive composite | High | Very high | Candidate for inexpensive resistive electrodes, experimental strain/contact sensors, antistatic coatings, sacrificial conductive traces, and surface-resistance experiments. | | Carbon-loaded resistive material | Medium-High | Very high | Could let ACE characterize homemade resistors or sensors and explore pressure- or strain-dependent resistance. | | Alum crystals | Low | Medium | Inexpensive, repeatable crystal-growth and environmental-test material that ACE could monitor alongside Rochelle salt. | | Casein-based dielectric or plastic | Low | Medium | Homemade insulating material for dielectric, humidity, and ageing characterization. | | Starch/gelatin polymer films | Low | Medium-High | Inexpensive experimental humidity-sensitive and dielectric materials. | | Iron-tannate complexes | Low-Medium | Medium | Candidate for corrosion, surface-chemistry, optical-sensing, and electrical-sensing experiments. | | Salt-hydrate mixtures | High | High | Supports systematic PCM formulation experiments instead of committing the programme to one thermal-storage material. | ## Routing notes - Current programme work remains SAT preparation, cell qualification, and crystallization control. - Graphite and conductive-composite work should reference the recorded Black Donald specimen without presuming that specimen's composition. - Plating-electrolyte and plating-pen concepts remain separate experimental proposals; this register does not authorize a formulation or ACE connection. - Future ACE use must remain electrically and revision agnostic until a specific interface proposal is reviewed through the applicable project rules. ## Reviewed candidates ### Sodium citrate / citrate salts - **Disposition:** Pursue later, after the SAT cell baseline. - **Preferred material:** Trisodium citrate dihydrate, CAS `6132-04-3`; ACS/reagent grade preferred for reproducibility. - **Role:** Complexing and buffering additive that can slow and control metal deposition; it is not a metal source or complete plating bath. - **First experiment:** Compare otherwise identical copper-plating coupon runs with and without a documented citrate concentration. - **Critical constraint:** Retain all metal-bearing bath, rinse, gel, filter, and wipe waste. Citrate can keep metal ions dissolved and complicate ordinary precipitation or disposal. - **ACE routing:** Characterize with a current-limited bench supply first. Only consider ACE logging or control after the chemistry is repeatable. ### Calcium alginate hydrogel - **Disposition:** Pursue as a plating-pen electrolyte-carrier candidate. - **Initial role:** Mechanically retain a conductive liquid at a controlled wet contact; do not treat the gel itself as the electrolyte or metal source. - **First experiment:** Prepare small calcium-alginate pads with a benign conductive salt solution and compare conductivity, leakage, contact quality, drying, shrinkage, durability, and reuse. - **Gate before plating chemistry:** Demonstrate stable physical contact and ion transport without tearing, uncontrolled leakage, or unacceptable drying. - **Critical constraints:** Calcium and plating-metal ions may alter the gel or contaminate the bath. Keep metal-bearing trials and their waste separate until compatibility is characterized. - **Approved plan:** `Chemistry/Hydrogels/NanoArc_Hydrogel_Electrolyte_Carrier_Screen_Rev0.md` ### Agar / gel-electrolyte formulations - **Disposition:** Retain as the low-cost plating-pen Plan B and direct alginate comparison material. - **Initial role:** Thermally set carrier for a conductive liquid; ordinary agar is suitable for proof-of-concept work, while agarose is the more consistent but more expensive laboratory option. - **First experiment:** Prepare agar and calcium-alginate pads with the same benign conductive salt solution, then compare conductivity, leakage, contact, drying, shrinkage, thermal stability, durability, and reuse. - **Advantages:** No calcium cross-linker, readily available, inexpensive, shapeable, and remeltable. - **Critical constraints:** Preparation requires heat; the gel may soften, release water, shrink, tear, or vary between food-grade products. - **Approved plan:** Shared with the alginate route in `Chemistry/Hydrogels/NanoArc_Hydrogel_Electrolyte_Carrier_Screen_Rev0.md`. ### Graphite/binder conductive composite - **Disposition:** Pursue as an inexpensive conductive-material and sensor characterization programme. - **Candidate uses:** Conductive coatings, contact or pressure sensors, bend or strain sensors, disposable resistors, experimental traces, and low-current electrodes. - **First experiment:** Produce fixed-geometry coupons with documented, increasing graphite-to-binder mass ratios. Measure resistance, repeatability, pressure response, temperature drift, adhesion, flexibility, and ageing. - **Initial material:** Use commercial graphite powder or pencil graphite so particle identity and the test method can be established first. - **Specimen constraint:** Do not grind or consume Black Donald specimen BDG-01 until its composition and dust hazards are better characterized and Tristan explicitly authorizes destructive sampling. - **ACE routing:** Treat this initially as a passive material-characterization target. Any excitation limits or hardware interface require a later reviewed experiment plan. ### Carbon-loaded resistive material - **Disposition:** Defer and fold into Phase 2 of the graphite/binder programme; do not create a separate project or procurement effort. - **Candidate material:** Documented conductive-grade carbon black, or a graphite/carbon-black blend, only if graphite coupons cannot reach the needed resistance or pressure sensitivity. - **Do not substitute:** Toner, tire residue, chimney soot, generic black pigment, or other unknown carbon sources are not acceptable substitutes. - **Constraint:** The exceptionally fine powder presents a substantially greater contamination and inhalation-control burden than graphite. - **Revisit gate:** A defined performance shortfall from the graphite programme, an identified documented grade, and an acceptable dust-handling method. ### Alum crystals - **Disposition:** Defer as an educational or post-NanoArc experiment. - **Retained use:** Inexpensive, accessible crystallization target for checking camera-based event detection, temperature logging, and environmental records. - **Limitation:** No presently identified direct contribution to RevA, PCM storage, or the plating-pen programme. - **Revisit gate:** A need for a predictable calibration material for the crystallization-observation system. ### Casein-based dielectric or plastic - **Disposition:** Defer to post-NanoArc materials experimentation. - **Possible use:** Humidity, ageing, dimensional-change, and leakage-resistance characterization of a homemade protein-based material. - **Not approved for:** Functional electrical insulation, safety barriers, or any voltage-withstand claim. - **Constraints:** Moisture sensitivity, shrinkage, warping, biological growth, and recipe-dependent properties make it unsuitable as an engineering dielectric. - **Chemistry boundary:** Do not use historical formaldehyde-hardening methods. ### Starch/gelatin polymer films - **Disposition:** Defer and combine with the post-NanoArc casein/biopolymer materials programme. - **Most promising use:** Experimental humidity-sensitive resistive or capacitive specimens rather than structural plastic or insulation. - **Possible measurements:** Resistance, capacitance, dimensional change, hysteresis, drying recovery, cracking, and ageing versus relative humidity. - **Not approved for:** Functional electrical insulation or safety barriers. - **Constraints:** Swelling, curling, cracking, biological growth, plasticizer migration, and poor batch consistency. ### Iron-tannate complexes - **Disposition:** Defer to post-NanoArc corrosion and optical-sensing research. - **Possible use:** Visible corrosion indicators and studies of optical or electrical change during oxidation, moisture exposure, and ageing. - **Current relevance:** No compelling role identified for ACE RevA, PCM cells, or the plating-pen programme. - **Constraints:** Household tannin sources are poorly defined; mixtures may be acidic, promote corrosion, produce persistent stains, and have limited or inconsistent electrical properties. ### Salt-hydrate mixtures - **Disposition:** Pursue as a later PCM-development phase. - **Purpose:** Screen controlled binary mixtures for useful changes in transition temperature, supercooling, cycling stability, or application range. - **Prerequisites:** Complete the pure-SAT baseline and separately characterize the selected nucleator and thickener routes first. - **Method boundary:** Test one documented composition at a time against the pure-SAT control; do not combine multiple uncharacterized additives or salts. - **Critical measurements:** Transition temperatures, usable thermal storage, supercooling, phase separation, hydrate-state change, corrosion, mass retention, and repeatability over cycling. - **Failure risks:** Lower energy density, irreversible segregation, corrosion, or a formulation that performs once but drifts during repeated cycles.