▎ 摘　　要

NOVELTY - Carbogenic nanoparticle-conducting polymer composite ink dispersed in water, where the carbogenic nanoparticle is reduced graphene oxide. The carbogenic nanoparticle-conducting polymer composite ink dispersed in water, chosen from graphene oxide (R-GO)-polypyrrole (PPy) composite ink, carbon quantum dots (CQD)-polyaniline (PANI) composite ink, R-GO-PANI composite ink, CQD-polythiophene (PTH) composite ink, R-GO-PTH composite ink, CQD-polyacetylene (PA) composite ink, R-GO-PA composite ink, CQD-poly(para-phenylene) (PPP) composite ink, R-GO-PPP composite ink, CQD-poly(phenylenevinylene) (PPV) composite ink, R-GO-PPV composite ink, CQD-polyfuran (PF) composite ink, R-GO-PF composite ink, or their combinations. USE - The composite ink is used for making a thin film coated printed circuit board (PCB) which is used for a volatile organic compound (VOC) sensor and a moisture sensor. The thin film coated PCB is used for detecting moisture, VOCs or both in a sample (all claimed). The composite ink is used in sensing and detection of moisture and VOCs under average temperature, pressure, and humidity conditions, and used as an active component for designing efficient sensors for moisture or VOCs. The composite ink is used as a sensing component in a moisture sensor or VOC sensor. The CQD-PPy composite ink is used to make a sensor that detects and differentiates between different VOCs. The sensor is used to detect to either detect moisture or selectively detect VOCs and their mixture in the presence of moisture. The thin film is used as the sensing component of a moisture sensor or a VOC sensor. ADVANTAGE - The device can accurately detect moisture and VOCs, and include: fabrication of a PCB using a colloidal ink; building a low-cost and portable device; and designing a sensor that can be regenerated and reused multiple times; and, for VOC detection, reducing the false-positive result due to hindrance of moisture. The ink is water-dispersible. The composite ink includes advantages of: ability to work as a flexible substrate in moisture sensors (humidity sensors) and VOC sensors; increased storage time at room temperature; processable by spin-coating on PCBs or other electrodes; improved dispersion (i.e., the carbogenic nanoparticlesare well dispersed making the colloidal stability form better thin films). The composite ink has advantages of: one to one replacement of conventional conducting polymer-based sensors; usability without the need for approval of any governing body; environmentally-friendly; inexpensive, easily scalable, and easy to use; easily stored; robust and inert to environmental fluctuation; operates rapider compared to presently available sensors; may be regenerated at ambient conditions; able to distinguish between VOCs of the same homologous group; able to distinguish between VOCs of two different functional groups. The CQD-PPy composite ink is used to make a sensor that detects and differentiates between different VOCs for the following reasons: CQD-PPy composite ink may be spin-coated on the PCB to form a thin transparent film; CQD-PPy composite ink is not affected by or responsive to moisture, which reduces the false-negative results; and CQD-PPy composite ink is water-based and may be fabricated over the PCB, hence making it cost-effective. The composite ink and the sensor (VOC or moisture) can be produced at relatively low expense using readily available, environmentally friendly materials. The moisture sensor may detect moisture rapidly in 20-60 seconds, or within 30 seconds of exposure. The moisture sensor may be regenerated (dried and ready for reuse) in 50-150 seconds, in 50-100 seconds, or within 100 seconds after each exposure. The composite ink is temperature stable such that a sensing component made with the composite inks may be subjected to any conventional method for regeneration, such as blown with nitrogen or heated by a micro-heater to allow desaturation and removal of the VOC and/or moisture, and allow reuse of the sensing component. The composite ink is respond electronically to VOCs, and has able to detect very low content of VOC (ppb), such as low as 10 ppb. The composite ink may be converted into a stable thin film by spin-coating and used in the sensing and detection of moisture and VOCs under average temperature, pressure, and humidity conditions. The thin film is able to detect the very low content of the analyte (ppb) as low as 10 ppb. The composite ink shows selective chemo resistivity by showing specific patterns in currentvoltage (I-V) characteristics. The resulting R-GO-conducting polymer composite is highly dispersible in water and showed high performance as the active sensor material for moisture and VOC sensor, respectively. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) a thin film coated printed circuit board (PCB) comprising a thin film of the carbogenic nanoparticle-conducting polymer composite ink, or a thin film of CQD-PPy composite ink or R-GO-PPy composite ink; (2) a method of making a thin film coated PCB comprising (a) treating the PCB under a UV lamp at 260-400 nm for 15-60 minutes, and (b) spin-coating the treated PCB with a carbogenic nanoparticle-conducting polymer composite ink comprising (b1) horizontally positioning the treated PCB on a rotating disk of a spin-coating machine, under vacuum, (b2) coating the substrate with a small amount of the composite ink, (b3) rotating the coated PCB at one or more different speeds to obtain a first layer of composite ink on the PCB, and (b4) optionally repeating steps (b2) and (b3) one to four times to obtain a double, triple, quadruple or quintuple layer of composite ink to make the thin film on the PCB; (3) a volatile organic compound (VOC) sensor comprising the thin film coated PCB; (4) a method of detecting moisture, VOCs or both in a sample using the thin film coated PCB; and (5) a method of making a R-GO-conducting polymer composite ink comprising (a-1) preparing graphene oxide (GO), (b-1) suspending the GO in water, (c-1) adding an iron (II) salt and a polymer having either a carboxyl or a bisulfate group to the suspension to make an R-GO suspension, (d-1) acidifying the R-GO suspension, (e-1) adding a monomer of the conducting polymer to the acidified R-GO suspension to make a R-GO-conducting polymer composite suspension, and (f-1) evaporating the composite suspension to reduce the volume to the composite ink.