Textile Structure
how cloth is put together
Concept

Inter fibre pore — where it appears

The space between the fibres inside a yarn, a few micrometres across, set by the fibre diameter and the packing factor alone. It is far smaller than the pore between yarns, so it pulls harder and fills more slowly, and a cloth wicks by both at once.

Named by 8 essays across 3 fields — each of them below, with the objects they name alongside it.

The sett moves the flux and not the height. A 20 tex cotton yarn woven at every sett from 8 to 34 threads per centimetre. Above: the hole between the threads lifts from 27 to 234 mm as the cloth closes, while the space between the fibres lifts 6.37 m at every one of them — so the cloth's maximum is the flat line, and the sett does not touch it. Below: the permeability of those holes falls by a factor of 292 over the same range. Both curves are monotone, so there is no optimum — only an interval, ending at the jam at 34.6 threads per centimetre.

The sett decides how much, not how high

Every essay on wicking so far has found the sett deciding something. This one finds it deciding nothing at all: a cloth's maximum rise is 6.37 m at eight threads per centimetre and 6.37 m at thirty-four, because the sett cannot reach inside a yarn.

setting · Sett Two pore systems in one cloth — 24 threads per centimetre. A plain weave of 20 tex cotton in section, at 24 threads per centimetre, so the yarn is 167 µm across and the clear hole between two picks is 250 µm. That hole's hydraulic radius is 124.8 µm. Inside the yarn, fibres 14 µm across packed at 0.6 leave spaces of hydraulic radius 2.33 µm — 53 times finer, and by Jurin's law 53 times higher: 6.37 m against 119 mm. The yarn's interior is magnified 6 times and the two discs at the foot are the only part drawn at one scale.

How high a cloth wicks

A woven cloth has two capillary systems and they are a factor of twenty to a hundred apart. The one every diagram draws — the hole between four threads — lifts 119 mm. The one nobody draws, inside the yarn, lifts 6.37 m.

applied · Wicking A front on a thread with 8 per cent crimp. Three rows at one scale. The top row is the warp end laid out straight, with the wetted front marked at four equal quarters of its own length — which is where Washburn's law puts it at four times whose square roots are evenly spaced. The middle row is the same thread crimped at 8 per cent, so it covers 92.6 per cent of the paper the straight one did. The bottom row is the cloth, and the four fronts on it are the four above pulled back by 1.08. A coefficient is a length squared over a time, so it comes down by 1.1664 — exactly (1 + c)², with no property of the liquid or the fibre in it. The thread's thickness is not drawn and neither is the liquid: a meniscus in a 2.33 µm pore is finer than any line on this canvas.

Wicking is slower along a crimped thread

A front travelling up a warp end travels the thread's path, which is longer than the cloth by exactly the crimp. So the wicking coefficient measured on the fabric is the yarn's own divided by (1 + c)² — 14.3 per cent lost at eight per cent crimp, whatever the liquid.

applied · Wicking How high a strip wicks a finite supply, in four rooms. The steady height of the fine pore system's wicking front against the supply of sweat at the strip's foot, both on logarithmic scales, for a sheeting-weight strip in four rooms. Below each room's capacity the height is the supply over twice the evaporation from each face, a line of slope one that no cloth property moves. It meets the room's drying ceiling at the capacity — 43 g/(m·h) at 20 g/m²·h, ceiling 1064 mm; 100 g/(m·h) at 100 g/m²·h, ceiling 501 mm; 204 g/(m·h) at 400 g/m²·h, ceiling 255 mm; 400 g/(m·h) at 1500 g/m²·h, ceiling 133 mm — and past it the strip takes no more. The marks along the bottom are four sweat rates from rest to hard work, fed from a contact patch 50 mm tall.

A sweating cloth wicks as high as the room can dry it

Every wicking height so far has had its foot in unlimited water. Skin is not a reservoir: it supplies sweat at a rate, and a cloth fed at a rate stands where the supply equals what its faces lose — the supply over twice the evaporation, with no pore, fibre or thickness in it. The cloth decides only when it has had enough, and it says so all at once: the holes between its yarns stay empty until the fine pores are carrying ninety-nine per cent of what they can.

applied · Wicking A 50 tex yarn after 1, 4, 8 dips into a fibre that fills. The cross-section of a 50 tex cotton yarn after 1, 4, 8 twenty-second dips, each fibre shaded by the dye fixed at its distance from the surface, on one scale of shade for all three. The fibre's room for dye is finite and one dip at the bath's strength fills 20% of an empty fibre's, so each dip meets less affinity near the surface than the last and carries its dye further in. after 1 dip: ring 14% of the radius deep, the surface 20% full; after 4 dips: ring 18% of the radius deep, the surface 59% full; after 8 dips: ring 24% of the radius deep, the surface 83% full. With room to spare every dip would leave the first dip's 14%. The share is assumed; nothing here measures it.

A fibre that fills dyes deeper with every dip

Dipped eight times, a ring-dyed yarn is darker than after one dip but no deeper — if its fibres have room for all the dye they are offered. They do not: every dip's dye occupies some of the fibre's room, the next dip meets less affinity near the surface, and dye that is taken up less travels further before it is taken. How much further depends on one number the dip arithmetic never needed — the share of an empty fibre's room one dip fills — and eight dips turn that number into a ring 1.15 times deeper at five per cent and 1.68 times deeper at twenty.

finishing · Dyeing How tall a skin contact can be before its cloth floods. The tallest patch of skin contact whose cloth keeps the holes between its yarns empty, against the sweat rate, on logarithmic axes, for a sheeting-weight cloth in rooms evaporating 20, 100, 400, 1500 g/m²·h from each face. The patch evaporates from its outer face only and hands its surplus to the free cloth above, which spreads it until the fine system's capacity; so a contact floods when it is taller than 98.9% of that capacity over the surplus. Below the room's own evaporation rate no contact of any size floods. In an ordinary room a run floods any contact taller than 247 mm and hard work any taller than 90 mm.

Wicking borrows drying area from the cloth that is not touching

A shirt is fed with sweat across the whole of the skin it touches, not at the foot of a strip. Through its own thickness the cloth could pass sweat a hundred thousand times faster than a body makes it, so a patch pressed flat never lacks capacity; what it lacks is drying area, because it can give water to the room only from its outer face. Pressed flat everywhere, it floods as soon as the sweat exceeds the room's evaporation — light work, in an ordinary room. With free cloth above the contact, wicking carries the surplus to faces that are not touching, and the sweat decides how much area it needs: three times the contact's at a run, whatever the contact's size.

applied · Wicking A 50 tex yarn after eight dips, with its pores open and filling. The cross-section of a 50 tex cotton yarn after eight twenty-second dips into a fibre one dip fills by 20%, each fibre shaded by the dye fixed at its distance from the surface, on one scale of shade. open pores: the ring 24% of the radius deep, the surface 83% full; the dark shade's pigment, all in the pores: the ring 22% of the radius deep, the surface 83% full; pores 90% filled at a full fibre: the ring 16% of the radius deep, the surface 83% full. One dip leaves 14%. The middle section is the most a dark denim's indigo could clog its pores, every grain placed in them; the right is a clog no denim's pigment is large enough to make.

Indigo is too little to close the pores it dyes through

Each dip of a fibre that fills carries its dye deeper, because the dye already fixed near the surface leaves less room there. But indigo is fixed as a solid, and some of it sits in the pores the next dip has to travel through, so a heavily dyed skin should also hold the next dip back. The two pull opposite ways, and which wins is decided by how much pigment there is. A dark denim's indigo, every grain of it placed in the pores, fills at most a fifth of them at the surface and takes back about a seventh of the ring's deepening — under two micrometres. The surface fills at the same rate whatever the pores do, so two cross-sections still tell the two effects apart.

finishing · Dyeing The ring across eight dips, for each fibre. The ring's depth after each of eight twenty-second dips, where an empty fibre left in the bath for good would fill by 20% a dip. instant fibre: 14.0% after one and 23.5% after eight; τ = 20 s: 13.0% after one and 19.6% after eight; τ = 100 s: 23.1% after one and 26.1% after eight; τ = 400 s: 35.5% after one and 36.6% after eight. An instant fibre earns its ring by saturating the skin dip by dip. A slow one starts near its final depth, since it never fills its skin.

A slow fibre starts its ring deep

Every account of an indigo dip here lets a cotton fibre take its dye at once. Give the fibre a clock of its own and the ring does not simply run deeper, which is what the question seemed to ask. A clock of a few seconds makes the ring shallower, by nearly a fifth at most, and only past about twenty-six seconds does it run deeper than an instant fibre's. Two sections tell the accounts apart that one cannot: an instant fibre earns its ring dip by dip, from 14 to 23.5 per cent of the radius over eight dips, and a fibre with a hundred-second clock starts at 23 and ends at 26.

finishing · Dyeing

Named alongside it

The objects these essays reach for when they reach for this one.

WickingDenimDye affinityFibrePermeabilityPore radiusRing dyeingWashburn's lawAbrasionContact angleHydraulic radiusJurin's law

All concepts