| HS Code | 577067 |
| Chemical Name | Polyvinyl Alcohol |
| Cas Number | 9002-89-5 |
| Chemical Formula | (C2H4O)n |
| Appearance | White to cream granular powder or pellets |
| Water Solubility | Soluble in water at temperatures above 80°C; limited solubility at room temperature |
| Degree Of Hydrolysis | Typically 86-89% or 98-99% depending on grade |
| Viscosity | 4-70 mPa·s (4% aqueous solution at 20°C) |
| Ph Value | 5.0-7.0 (aqueous solution) |
| Density | 1.19-1.31 g/cm³ |
| Melting Point | 180-230°C (decomposes before melting for fully hydrolyzed grades) |
| Glass Transition Temperature | Room temperature ~25°C (varies with plasticizer content) |
| Tensile Strength | 20-70 MPa depending on molecular weight and film preparation |
| Elongation At Break | 10-400% depending on moisture content and plasticization |
| Thermal Decomposition Temperature | Stable up to ~200°C; rapid decomposition above 250°C |
As an accredited Polyvinyl Alcohol (PVA) for Conductive Polymer Templates factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | 25 g in a sealed amber glass bottle with polypropylene cap, labeled, nitrogen-purged for moisture protection and template stability. |
| Container Loading (20′ FCL) | Polyvinyl Alcohol for Conductive Polymer Templates ships as a 20′ FCL, packed in sealed bags on pallets, safely secured for transit. |
| Shipping | Polyvinyl Alcohol (PVA) for Conductive Polymer Templates ships as a dry, water-soluble powder in sealed, moisture-resistant containers. Store away from humidity and heat. Not classified as dangerous goods; standard ambient transport is suitable. Ensure intact packaging and secure labeling to prevent spills during transit. |
| Storage | Store Polyvinyl Alcohol (PVA) for conductive polymer templates in a tightly sealed, original container in a cool, dry, well-ventilated area, away from moisture, heat, and direct sunlight. Avoid exposure to airborne dust. Keep separated from oxidizing agents and ignition sources. Maintain ambient temperatures between 15–25°C to preserve polymer integrity and template performance. |
| Shelf Life | Store in cool, dry conditions; typically stable for 2 years when sealed properly. |
In the production of optoelectronic-grade transparent electrodes, polyvinyl alcohol (PVA) serves as a sacrificial porogen in the aqueous processing of poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) formulations. Slot-die coating onto pre-annealed polyethylene terephthalate (PET) under 30–40% RH conditions minimizes PVA moisture absorption that otherwise induces dewetting defects. The PVA-to-PEDOT:PSS solid ratio is maintained between 1:2 and 2:1, with rheology adjusted to 800–1200 mPa·s at 10 s⁻¹ for defect-free meniscus guidance. After coating, a staged thermal cure—ramping from 80 °C to 130 °C over 15 min—removes the PVA template, leaving a nanoporous PEDOT:PSS layer that increases specific surface area and relieves internal stress. Transmission exceeds 90% at 550 nm (measured per ASTM D1003) while sheet resistance drops below 100 Ω/sq, satisfying the optoelectronic requirements of flexible active-matrix organic light-emitting diode (AMOLED) panels and projected-capacitive touch sensors. Cross-hatch adhesion tested according to ASTM D3359-17 routinely achieves classification 5B when an epoxy-silane primer is incorporated at 0.2 wt%. Electromagnetic compatibility of the final film stack is validated under IEC 61249-2-21 halogen-free substrate constraints, and RoHS 2011/65/EU compliance is confirmed via XRF screening for restricted substances. Production-scale coating lines running at 15–25 m/min report that viscosity drift exceeding ±8% within a 4-hour pot life leads to transverse striping, a failure mode controllable only through chilled dispense reservoirs held at 8–12 °C.
Surface resistivity between 106 and 109 Ω/sq per IEC 61340-5-1 is obtained by applying PVA-stabilized PEDOT:PSS dispersions via micro-gravure to biaxially oriented polypropylene (BOPP) or PET. PVA addition at 1–3 wt% of total solids prevents pigment bodying and confers a near-Newtonian flow suitable for 140–180 line/cm engraved cylinders. End products include thermoformed trays and injection-molded totes for ESD-sensitive semiconductor packaging, where tribocharging below 50 V is mandatory per ANSI/ESD S20.20.
Wet spinning of homogeneous PVA/polyaniline (PANI) blends through a 50 µm spinneret into a pH 1.5–2.0 sulfate coagulation bath produces filaments with core‐sheath phase separation critical to subsequent drawing. PVA-to-PANI weight ratios range from 70:30 to 50:50, with dodecylbenzenesulfonic acid serving as both dopant and dispersant at a 1:1 molar ratio to aniline units. Hot-drawing at 90–110 °C to a draw ratio of 3.5–4.5 orients PANI chains within the PVA matrix, yielding electrical conductivities of 5 × 10⁻² to 2 × 10⁻¹ S/cm measured by four-point probe per ASTM F390. Over-drawing beyond ratio 5.0 causes fibrillation and a conductance cliff-drop due to stress-induced dedoping, a restriction routinely encountered on multi-stage drawing lines with heated godets. Conductive yarns meeting ISO 10993-5 cytotoxicity criteria are knitted into antistatic workwear and resistive heating panels for medical rehabilitation textiles, while silver-coated variants achieve shielding effectiveness of >30 dB at 1 GHz under ASTM D4935-18.
| Application | Standard | Key Clause / Method |
|---|---|---|
| Transparent electrode | IEC 61249-2-21 | Halogen-free substrate requirement |
| Anti-static packaging | IEC 61340-5-1, ANSI/ESD S20.20 | Surface resistance ≤109 Ω, charging <50 V |
| Conductive fiber | ISO 10993-5, ASTM D4935-18 | Cytotoxicity (medical fabrics), shielding effectiveness |
| Biosensor electrode | ISO 13485:2016, EN 60601-1 | Medical device QMS, basic safety |
| Capacitor cathode | IEC 62391-1, AEC-Q200 | Fixed electric double-layer capacitors, automotive reliability |
| Conductive ink | RoHS 2011/65/EU | Restricted substance limits |
Melt-spinning is avoided because PVA undergoes thermal decomposition near 200 °C before PANI can flow; therefore wet-jet spinning constitutes the only scalable route. Coagulation bath composition—typically 10–15 wt% Na₂SO₄ with 0.5 M H₂SO₄—determines the rate of PVA skin formation and PANI interdiffusion, setting the core porosity accessible for subsequent doping/de-doping steps. In-line dielectric spectroscopy of the spinline at 10 kHz monitors real-time coagulation state, alerting to bath concentration fluctuations beyond ±0.5 wt% that cause filament breakage on the first godet. The as-spun tow is then subjected to a three-stage washing cascade to reduce residual sulfate ions below 50 ppm, a threshold above which corrosion of metallic heating wires in the final textile product becomes measurable within 500 hours of accelerated aging at 85 °C/85% RH.
A 2.5–5 wt% aqueous PVA solution containing glucose oxidase (≥100 U/mg) is drop-cast onto a screen-printed platinum working electrode and crosslinked with 0.1 vol% glutaraldehyde for 4 hours at 4 °C. The hydrogel is then immersed in a 10 mM EDOT monomer solution containing 0.1 M LiClO₄, and potentiostatic polymerization at +0.95 V versus Ag/AgCl deposits a PEDOT network interpenetrating the PVA template. Cyclic voltammetry between ‑0.2 and +0.8 V at 50 mV/s (per ISO 15181-2 protocol adapted for biosensors) confirms a peak-to-peak separation below 70 mV and a linear glucose response from 0.5 to 20 mM. The primary operational boundary is the swelling-driven delamination of the hydrogel layer when storage humidity exceeds 75% RH, resulting in an amperometric drift rate of >2% per hour. Manufacturing-scale failure analysis on continuous glucose monitoring sensor strips shows that PVA batches with a degree of hydrolysis below 95% exhibit excessive water solubility and unacceptable lot-to-lot enzyme leakage, necessitating incoming acceptance testing via ISO 1628-3 dilute solution viscometry and 1H-NMR degree of hydrolysis verification.
In solid aluminum electrolytic capacitor cathode formation, PVA functions as a viscosity modifier and secondary template during in-situ chemical oxidative polymerization of EDOT on etched aluminum foil. The oxidant, iron(III) p-toluenesulfonate in n-butanol, is pre-mixed with 0.5–1.5 wt% PVA (relative to total solution mass) to achieve a Brookfield viscosity of 35–60 mPa·s (ISO 2555), ensuring uniform meniscus coverage during vertical withdrawal coating at 2–5 mm/s. The polymerization proceeds at 25–30 °C for 10 min, followed by a stepped cure from 130 °C to 155 °C that removes the PVA template and residual solvent. A critical quality parameter is the equivalent series resistance (ESR), which rises from an ideal 12 mΩ to above 45 mΩ if residual PVA exceeds 0.2 wt% of the cathode layer mass, a sensitivity confirmed by IEC 62391-1 impedance measurements at 100 kHz. PVA removal efficiency hinges on a post-cure water leaching step conducted at 90 °C for 20 min; shortening this duration by even 5 min elevates the PVA residue above the critical threshold. Automotive-grade parts qualified to AEC-Q200 additionally require a 1000-hour endurance test at 125 °C with applied rated voltage, during which capacitance degradation must stay within ±20%. Production data indicates that the combined PVA template and oxidative polymerization approach achieves a specific capacitance of 300–450 µF/cm² at 1 kHz, a bandwidth where traditional manganese dioxide cathodes fall short.
| Application | PVA Addition Level | Critical Process Condition | Failure Threshold |
|---|---|---|---|
| Transparent electrode | 1:2–2:1 relative to PEDOT:PSS solids | Coating humidity 30–40% RH | Viscosity drift >±8% in 4 h |
| Anti-static film | 1–3 wt% of solids | Rotogravure viscosity <140 mPa·s | Resistivity >109 Ω/sq |
| Conductive fiber | 50–70 wt% of blend with PANI | Draw ratio 3.5–4.5, 90–110 °C | Draw ratio >5.0 causes dedoping |
| Biosensor electrode | 2.5–5 wt% in hydrogel | PEDOT polymerization at +0.95 V | Storage RH >75% causes drift |
| Capacitor cathode | 0.5–1.5 wt% in oxidant solution | Water leaching 90 °C, 20 min | Residual PVA >0.2 wt% ⇒ ESR >45 mΩ |
| Conductive ink | 0.1–0.5 wt% of total formulation | Jetting viscosity 8–12 mPa·s | Post-cure time <10 min yields >50 Ω/sq |
Conductive ink formulations for drop-on-demand inkjet printing often incorporate 0.1–0.5 wt% PVA to target a jetting viscosity of 8–12 mPa·s at 40 °C, as measured by ISO 3104. PVA functions as a sacrificial rheology modifier and jetting reliability enhancer; after ink deposition and a thermal post-cure at 150 °C for 10 min, the PVA decomposes, leaving a PEDOT:PSS pattern with sheet resistance below 50 Ω/sq. Printed RFID antennas on flexible paper substrates and fine-pitch circuit traces on polyimide constitute the major end uses. Batch-to-batch PVA molecular weight variation outside ±5 kDa from a nominal 31 kDa results in satellite droplet formation and nozzle plate flooding, defects documented on industrial printheads operating above 10 kHz firing frequency.
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Polyvinyl alcohol grade PVA-CP-88 (and its sub-variant PVA-CP-88XF) is a high‑saponification, medium‑viscosity thermoplastic designed exclusively as a water‑soluble sacrificial template for the fabrication of conductive polymer micro‑ and nanostructures. The product is differentiated by an ash content held below 0.2 wt% (measured per JIS K6726 oxide residue method), a residual sodium acetate concentration consistently under 0.1 wt%, and a heavy‑metal profile compliant with RoHS Directive 2011/65/EU Annex II and REACH Annex XVII. These purity metrics are critical when the template must be fully removed without leaving ionic residues that dope or screen the charge‑transport pathways in poly(3,4‑ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), polypyrrole, or polyaniline films. Primary applications span sacrificial lift‑off resists in nanoimprint lithography, water‑dissolvable mandrels for electrochemical deposition of freestanding conductive polymer meshes, and temporary structural frameworks for carbon nanotube aerogels that are later eliminated by aqueous dissolution at 60–95 °C.
| Property | PVA-CP-88ST | PVA-CP-88XF | Test Method |
|---|---|---|---|
| Degree of hydrolysis | 97.5–98.5 mol% | 98.0–99.0 mol% | JIS K6726 (back‑titration) |
| 4 % aqueous viscosity at 20 °C | 24–28 mPa·s | 26–30 mPa·s | ASTM D2196 (Brookfield LV, spindle 1, 60 rpm) |
| Ash content (as Na₂O) | 0.08–0.15 wt% | 0.04–0.08 wt% | JIS K6726 |
| Volatile matter | 4.0–5.5 % | 3.5–5.0 % | ISO 3251:2019 (105 °C, 3 h) |
| pH (4 % aqueous) | 5.5–7.0 | 6.0–7.5 | ASTM D7928 |
| Tensile strength (film cast from 8 % solution) | 38–45 MPa | 42–50 MPa | ASTM D882 (gauge length 50 mm, 5 mm/min) |
| Elongation at break | 6–9 % | 5–8 % | ASTM D882 |
| Glass transition temperature (Tg) | 73 ± 2 °C | 74 ± 2 °C | ISO 11357‑2:2020 (second heat, 10 °C/min, N₂) |
The narrow acetate window (1.0–2.5 mol%) preserves complete cold‑water solubility while providing sufficient intermolecular disorder to suppress excessive crystallinity development during drying. Differential scanning calorimetry under ISO 11357‑3 reveals a melting endotherm with peak at 218–226 °C (ΔHf ≈ 38–45 J/g for film cast from 12 % solution), confirming a partially crystalline structure that is nonetheless fully disrupted by hydration. The XF grade incorporates a 0.45 µm absolute‑rated in‑line filtration step before spray‑drying, reducing gel‑particle counts to fewer than 5 particles/mm² in a 10 µm‑thick film when inspected under 62× dark‑field illumination; this is essential when the template layer serves as a mechanical support for sub‑100 nm conductive polymer coatings that would otherwise bridge defects and form micro‑shorts.
Removal of the PVA template from a formed conductive polymer stack typically occurs in heated deionized water or dilute (0.05–0.2 M) aqueous acetic acid at 70–85 °C. Gravimetric dissolution rates determined by a modified ASTM D570 immersion protocol (specimen size 25 mm × 25 mm, agitation via 40 kHz ultrasonic bath) show a rate of 12–14 mg/cm²·min for a 20 µm‑thick PVA-CP-88ST film in stirred water at 80 °C. Below 60 °C the rate falls below 2 mg/cm²·min, extending cycle time beyond 40 min for complete clearance of a 50 µm layer; this creates a practical lower process‑temperature limit. More critically, a heating ramp exceeding 5 °C/min when transitioning from ambient to the dissolution bath induces asymmetric swelling of the PVA template under the conductive polymer overlayer. The differential volumetric expansion (water uptake reaches 12–16 % by mass within the first 30 s at 80 °C) generates interfacial shear stresses above 2.5 MPa, sufficient to delaminate thin (< 100 nm) PEDOT:PSS films from the substrate. Observed blister diameters of 0.3–1.2 mm in blister‑probe tests correlate with a loss of more than 40 % of the electrochemically active area. Process specifications therefore mandate a controlled immersion sequence: pre‑heating the substrate to 50 ± 3 °C over 15 min in a humidity‑controlled chamber (RH < 30 %) before transfer into the 80 °C bath, limiting ramp to 2 °C/min. When the template thickness exceeds 80 µm, a staged dissolution with a 20‑min hold at 65 °C is introduced to allow the swelling front to propagate without catastrophic blister nucleation.
PVA grades with hydrolysis levels exceeding 99.5 mol% exhibit a film elongation at break of merely 1.8–2.3 % (ASTM D882, 50 % RH conditioning), rendering them unusable as free‑standing template foils without plasticizer addition. The PVA-CP-88 series, maintained at 1.0–2.5 mol% residual acetate, delivers elongation values of 8.5 ± 1.2 % for the ST grade in the machine direction. This compliance is achieved without external plasticizers that would diffuse into the nascent conductive polymer and alter its doping state. Dynamic mechanical analysis (ASTM D5026, film tension, 1 Hz) places the β‑relaxation (associated with side‑chain motion of acetate groups and adsorbed water) at −18 °C, providing mechanical energy dissipation that prevents cracking during the 0.5–3 bar conformal imprinting pressures typical of soft‑UV‑nanoimprint lithography. The penalty is a slight depression of the Vicat softening temperature by 4–6 °C relative to a fully hydrolyzed analogue of equivalent viscosity; however, the processing envelope up to 120 °C templates well‑above the 85 °C pre‑exposure bake used to remove residual solvent from spin‑coated films, and thus does not impose a practical restriction.
A processing conflict emerges when the PVA template must survive a thermal annealing step designed to enhance the conductivity of the overlying PEDOT:PSS layer. Post‑deposition annealing at 120–140 °C for 10–30 min—common for achieving conductivities above 800 S/cm—increases the PVA crystalline fraction by 8–12 % (quantified by deconvolution of X‑ray diffraction peaks at 2θ = 19.5° and 22.7°). Crystallites resist hydration, extending the dissolution induction period from < 2 min for an as‑cast amorphous film to 6–10 min at 80 °C. Under identical conditions, a 20 µm film annealed at 120 °C leaves a residue mass of 0.4–0.8 % of the initial dry weight, detected as a sub‑monolayer skin that shifts the water contact angle of the underlying substrate from < 5° to 28–32°. This residue contains carboxylate‑rich segments formed by mild thermal oxidation and is sufficient to impede ohmic contact when silver paste electrodes are subsequently screen‑printed. Mitigation relies on incorporating a 0.5–1.0 wt% hydrogen peroxide pre‑treatment of the dissolution bath, which cleaves backbone chains at the oxidised sites without etching the conductive polymer, provided the PEDOT:PSS layer is thicker than 50 nm; published data for this specific configuration remains limited to single‑laboratory factorial studies and has not been corroborated on 300 mm wafer‑scale continuous‑flow equipment.
For nanoimprint lithography lift‑off processes, PVA-CP-88XF is dissolved in ultrapure water (18.2 MΩ·cm) to an 8–12 % solids content and filtered through a 0.2 µm nylon membrane immediately before spin‑coating. A two‑step spin profile (500 rpm for 10 s, 2000 rpm for 60 s) on HMDS‑primed silicon yields a film thickness of 115 ± 5 nm after a 100 °C hot‑plate bake for 90 s. The low surface free energy of the dried film (37–40 mN/m, determined by Owens‑Wendt regression of diiodomethane and water contact angles per ASTM D7490) facilitates clean separation from fluorinated quartz mold surfaces. Imprint pressure is held at 18 bar under 365 nm UV exposure (400 mJ/cm²), after which the residual layer is removed by a brief O₂ plasma descum (20 s, 50 W, 100 mTorr). Silver nanowire or PEDOT:PSS dispersions are then slot‑die coated into the template trenches, and the PVA is lifted off by immersion in water at 65 °C with megasonic agitation (950 kHz), leaving the conductive pattern. The entire sequence maintains critical dimension bias below 4 nm for feature sizes down to 80 nm half‑pitch, as verified by top‑down SEM metrology.
When cross‑sectional template thickness exceeds 50 µm, isotropic dissolution fronts advance from both edges and converge unevenly, encapsulating micron‑scale PVA pockets that are shielded from convective water flow. Scanning electron micrographs of freeze‑fractured PEDOT:PSS caps after template removal reveal residual deposits occupying 0.8–3.5 % of the cross‑sectional area, with a lateral distribution that follows the convective streamlines of the dissolution vessel. The consequence is an increase in sheet resistance of a 1 µm‑thick PEDOT:PSS film from 120 ± 15 Ω/sq to 310 ± 45 Ω/sq (measured by a four‑point probe, 1 mA current). The threshold for acceptable residue is application‑dependent: organic photovoltaic cells tolerate residues up to 0.5 % area without measurable fill‑factor degradation, whereas organic electrochemical transistors exhibit a 15–20 mV shift in threshold voltage per 0.1 % residue attributed to unintended counter‑ion trapping. For structures thicker than 30 µm, a programmed recirculation loop (2 L/min flow through a 0.5 mm nozzle array) that creates directed high‑velocity jets against the open edges is recommended. This arrangement reduces dissolution time by 35–40 % and pushes the residue limit below the 0.2 % area necessary for transistor gate‑dielectric integrity.
| Parameter | PVA-CP-88 | Polyvinylpyrrolidone (PVP K30) | Poly(methyl methacrylate) (PMMA, Mw 120k) | Sodium carboxymethylcellulose (Na‑CMC, DS 0.7) |
|---|---|---|---|---|
| Primary removal medium | Water at 60–95 °C | Water, ethanol, or acidic buffer | Acetone, chlorinated solvents | Water, alkaline solution |
| Residual inorganic ash after thermal decomposition (700 °C, air) | 0.04–0.15 wt% | 0.3–0.8 wt% (sulfated ash) | < 0.02 wt% | 15–25 wt% (soda ash) |
| Compatibility with aqueous PEDOT:PSS (pH 2–3) | Stable for >48 h at 4 °C | Partial protonation leads to complex coacervation after 6 h | Immiscible; requires organic solvent PEDOT:PSS formulation | Viscosity build‑up; gelation with PSS chains |
| Film formation method | Spin‑coat, slot‑die, spray, dip‑coat | Spin‑coat, wire‑bar | Spin‑coat, doctor blade from anisole | Wire‑wound rod, limited spin‑coat uniformity |
| Minimum reproducible film thickness (on Si) | 40 nm | 60 nm | 30 nm | 200 nm |
| Reflow temperature for gap filling | 75–90 °C (steam‑assisted) | 110–130 °C | 160–180 °C | None; decomposes above 200 °C |
| Post‑removal surface contamination (XPS C1s atypical peak) | < 0.5 at% above background | 1.2–2.8 at% N1s signal persists | 0.3–0.7 at% O–C=O signal | 3–6 at% Na1s remains after aqueous rinse |
The principal advantage of PVA over PVP is the absence of nitrogen‑containing residues that can act as n‑type dopants or charge‑trapping sites in conjugated polymer backbones. Over PMMA, PVA eliminates the need for flammable and ecotoxicological‑burdened ketone or chlorinated solvents, significantly simplifying waste‑stream handling under EPA 40 CFR Part 261 and EU Waste Framework Directive 2008/98/EC. Compared to Na‑CMC, the ash‑free nature of PVA avoids mobile sodium ions that diffuse through dielectric layers during device operation and alter flat‑band voltage by more than 500 mV in capacitance‑voltage measurements.
Solution preparation for all PVA-CP-88 grades demands deionized water (≤ 0.5 µS/cm) heated to 85–95 °C under a nitrogen blanket to suppress back‑bone cleavage by dissolved oxygen. A 2‑hour stir time with a helical ribbon impeller at 120 rpm is standard for a 10 wt% batch; the resulting solution is then de‑aerated for 30 min at −0.09 MPa gauge before being passed through a 0.45 µm absolute‑rated polypropylene depth filter. Ambient relative humidity above 65 % necessitates a pre‑drying protocol for the cast film at 40–50 °C for 20 min under a dry‑air stream (< 5 % RH) to prevent bubble entrapment during subsequent heating. The shelf life of a sealed drum stored at 10–25 °C is certified for 24 months from date of manufacture; once opened, the powder should be consumed within 60 days due to gradual moisture uptake that increases volatile content beyond the specified 5.5 %. An operational incompatibility exists with ferric chloride‑based oxidant solutions used for in‑situ pyrrole polymerization: the strongly acidic and oxidizing medium (pH < 1, redox potential > 0.77 V vs. SHE) attacks the 1,2‑diol backbone of PVA, resulting in chain scission and premature loss of template integrity within 2–4 hours at room temperature. Ammonium persulfate systems at concentrations below 0.1 M are acceptable alternatives when the polymerization temperature does not exceed 4 °C, as residual sulfate radicals are scavenged more slowly by the PVA chain.
